Commands
Index
Commands (Data Manipulation)
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SELECT INSERT UPDATE DELETE BACKUP CALL |
EXECUTE IMMEDIATE EXPLAIN MERGE INTO MERGE USING RUNSCRIPT SCRIPT |
SHOW Explicit table Table value WITH |
Commands (Data Definition)
Commands (Other)
Details
Click on the header of the command to switch between railroad diagram and BNF.
Non-standard syntax is marked in green. Compatibility-only non-standard syntax is marked in red, don't use it unless you need it for compatibility with other databases or old versions of H2.
Commands (Data Manipulation)
SELECT
SELECT |
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selectExpression |
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Selects data from a table or multiple tables.
Command is executed in the following logical order:
1. Data is taken from table value expressions that are specified in the FROM clause, joins are executed. If FROM clause is not specified a single row is constructed.
2. WHERE filters rows. Aggregate or window functions are not allowed in this clause.
3. GROUP BY groups the result by the given expression(s). If GROUP BY clause is not specified, but non-window aggregate functions are used or HAVING is specified all rows are grouped together.
4. Aggregate functions are evaluated.
5. HAVING filters rows after grouping and evaluation of aggregate functions. Non-window aggregate functions are allowed in this clause.
6. Window functions are evaluated.
7. QUALIFY filters rows after evaluation of window functions. Aggregate and window functions are allowed in this clause.
8. DISTINCT removes duplicates. If DISTINCT ON is used only the specified expressions are checked for duplicates; ORDER BY clause, if any, is used to determine preserved rows. First row is each DISTINCT ON group is preserved. In absence of ORDER BY preserved rows are not determined, database may choose any row from each DISTINCT ON group.
9. UNION, EXCEPT, and INTERSECT combine the result of this query with the results of another query. INTERSECT has higher precedence than UNION and EXCEPT. Operators with equal precedence are evaluated from left to right.
10. ORDER BY sorts the result by the given column(s) or expression(s).
11. Number of rows in output can be limited with OFFSET and FETCH clauses. OFFSET specifies how many rows to skip. Please note that queries with high offset values can be slow. FETCH FIRST/NEXT limits the number of rows returned by the query. If PERCENT is specified number of rows is specified as a percent of the total number of rows and should be an integer value between 0 and 100 inclusive. WITH TIES can be used only together with ORDER BY and means that all additional rows that have the same sorting position as the last row will be also returned.
WINDOW clause specifies window definitions for window functions and window aggregate functions. This clause can be used to reuse the same definition in multiple functions.
If FOR UPDATE is specified, the tables or rows are locked for writing. If some rows are locked by another session, this query will wait some time for release of these locks, unless NOWAIT or SKIP LOCKED is specified. If SKIP LOCKED is specified, these locked rows will be excluded from result of this query. If NOWAIT is specified, presence of these rows will stop execution of this query immediately. If WAIT with timeout is specified and some rows are locked by another session, this timeout will be used instead of default timeout for this session. Please note that with current implementation the timeout doesn't limit execution time of the whole query, it only limits wait time for completion of particular transaction that holds a lock on a row selected by this query.
This clause is not allowed in DISTINCT queries and in queries with non-window aggregates, GROUP BY, or HAVING clauses. Only the selected rows are locked as in an UPDATE statement. Rows from the right side of a left join and from the left side of a right join, including nested joins, aren't locked. Locking behavior for rows that were excluded from result using OFFSET / FETCH / LIMIT / TOP or QUALIFY is undefined, to avoid possible locking of excessive rows try to filter out unneeded rows with the WHERE criteria when possible. Rows are processed one by one. Each row is read, tested with WHERE criteria, locked, read again and re-tested, because its value may be changed by concurrent transaction before lock acquisition. Note that new uncommitted rows from other transactions are not visible unless read uncommitted isolation level is used and therefore cannot be selected and locked. Modified uncommitted rows from other transactions that satisfy the WHERE criteria cause this SELECT to wait for commit or rollback of those transactions.
Example:
SELECT * FROM TEST;
SELECT * FROM TEST ORDER BY NAME;
SELECT ID, COUNT(*) FROM TEST GROUP BY ID;
SELECT NAME, COUNT(*) FROM TEST GROUP BY NAME HAVING COUNT(*) > 2;
SELECT 'ID' COL, MAX(ID) AS MAX FROM TEST UNION SELECT 'NAME', MAX(NAME) FROM TEST;
SELECT * FROM TEST OFFSET 1000 ROWS FETCH FIRST 1000 ROWS ONLY;
SELECT A, B FROM TEST ORDER BY A FETCH FIRST 10 ROWS WITH TIES;
SELECT * FROM (SELECT ID, COUNT(*) FROM TEST
GROUP BY ID UNION SELECT NULL, COUNT(*) FROM TEST)
ORDER BY 1 NULLS LAST;
SELECT DISTINCT C1, C2 FROM TEST;
SELECT DISTINCT ON(C1) C1, C2 FROM TEST ORDER BY C1;
SELECT ID, V FROM TEST WHERE ID IN (1, 2, 3) FOR UPDATE WAIT 0.5;
INSERT
INSERT INTO |
| tableName |
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Inserts a new row / new rows into a table.
If column names aren't specified a list of all visible columns in the table is assumed.
When using DIRECT, then the results from the query are directly applied in the target table without any intermediate step.
Example:
INSERT INTO TEST VALUES(1, 'Hello')
UPDATE
UPDATE |
| tableName |
| SET setClauseList |
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FETCH |
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Updates data in a table. ORDER BY is supported for MySQL compatibility, but it is ignored. If FETCH is specified, at most the specified number of rows are updated (no limit if null or smaller than zero).
Example:
UPDATE TEST SET NAME='Hi' WHERE ID=1;
UPDATE PERSON P SET NAME=(SELECT A.NAME FROM ADDRESS A WHERE A.ID=P.ID);
DELETE
Deletes rows form a table. If FETCH is specified, at most the specified number of rows are deleted (no limit if null or smaller than zero).
Example:
DELETE FROM TEST WHERE ID=2
BACKUP
BACKUP TO fileNameString |
Backs up the database files to a .zip file. Objects are not locked, but the backup is transactionally consistent because the transaction log is also copied. Admin rights are required to execute this command.
Example:
BACKUP TO 'backup.zip'
CALL
CALL expression |
Calculates a simple expression. This statement returns a result set with one row, except if the called function returns a result set itself. If the called function returns an array, then each element in this array is returned as a column.
Example:
CALL 15*25
EXECUTE IMMEDIATE
EXECUTE IMMEDIATE sqlString |
Dynamically prepares and executes the SQL command specified as a string. Query commands may not be used.
Example:
EXECUTE IMMEDIATE 'ALTER TABLE TEST DROP CONSTRAINT ' ||
QUOTE_IDENT((SELECT CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE TABLE_SCHEMA = 'PUBLIC' AND TABLE_NAME = 'TEST'
AND CONSTRAINT_TYPE = 'UNIQUE'));
EXPLAIN
Shows the execution plan for a statement. When using EXPLAIN ANALYZE, the statement is actually executed, and the query plan will include the actual row scan count for each table.
Example:
EXPLAIN SELECT * FROM TEST WHERE ID=1
MERGE INTO
Updates existing rows, and insert rows that don't exist. If no key column is specified, the primary key columns are used to find the row. If more than one row per new row is affected, an exception is thrown.
Example:
MERGE INTO TEST KEY(ID) VALUES(2, 'World')
MERGE USING
MERGE INTO |
| targetTableName |
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USING tableExpression |
ON expression |
mergeWhenClause |
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Updates or deletes existing rows, and insert rows that don't exist.
The ON clause specifies the matching column expression.
Different rows from a source table may not match with the same target row (this is not ensured by H2 if target table is an updatable view). One source row may be matched with multiple target rows.
If statement doesn't need a source table a DUAL table can be substituted.
Example:
MERGE INTO TARGET_TABLE AS T USING SOURCE_TABLE AS S
ON T.ID = S.ID
WHEN MATCHED AND T.COL2 <> 'FINAL' THEN
UPDATE SET T.COL1 = S.COL1
WHEN MATCHED AND T.COL2 = 'FINAL' THEN
DELETE
WHEN NOT MATCHED THEN
INSERT (ID, COL1, COL2) VALUES(S.ID, S.COL1, S.COL2);
MERGE INTO TARGET_TABLE AS T USING (SELECT * FROM SOURCE_TABLE) AS S
ON T.ID = S.ID
WHEN MATCHED AND T.COL2 <> 'FINAL' THEN
UPDATE SET T.COL1 = S.COL1
WHEN MATCHED AND T.COL2 = 'FINAL' THEN
DELETE
WHEN NOT MATCHED THEN
INSERT VALUES (S.ID, S.COL1, S.COL2);
MERGE INTO TARGET T USING (VALUES (1, 4), (2, 15)) S(ID, V)
ON T.ID = S.ID
WHEN MATCHED THEN UPDATE SET V = S.V
WHEN NOT MATCHED THEN INSERT VALUES (S.ID, S.V);
MERGE INTO TARGET_TABLE USING DUAL ON ID = 1
WHEN NOT MATCHED THEN INSERT VALUES (1, 'Test')
WHEN MATCHED THEN UPDATE SET NAME = 'Test';
RUNSCRIPT
RUNSCRIPT FROM fileNameString scriptCompressionEncryption |
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FROM_1X |
Runs a SQL script from a file. The script is a text file containing SQL statements; each statement must end with ';'. This command can be used to restore a database from a backup. The password must be in single quotes; it is case sensitive and can contain spaces.
Instead of a file name, a URL may be used. To read a stream from the classpath, use the prefix 'classpath:'. See the Pluggable File System section.
The compression algorithm must match the one used when creating the script. Instead of a file, a URL may be used.
If QUIRKS_MODE is specified, the various compatibility quirks for scripts from older versions of H2 are enabled. Use this clause when you import script that was generated by H2 1.4.200 or an older version into more recent version.
If VARIABLE_BINARY is specified, the BINARY data type will be parsed as VARBINARY. Use this clause when you import script that was generated by H2 1.4.200 or an older version into more recent version.
If FROM_1X is specified, quirks for scripts exported from H2 1.*.* are enabled. Use this flag to populate a new database with the data exported from 1.*.* versions of H2. This flag also enables QUIRKS_MODE and VARIABLE_BINARY implicitly.
Admin rights are required to execute this command.
Example:
RUNSCRIPT FROM 'backup.sql'
RUNSCRIPT FROM 'classpath:/com/acme/test.sql'
RUNSCRIPT FROM 'dump_from_1_4_200.sql' FROM_1X
SCRIPT
SCRIPT |
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Creates a SQL script from the database.
NODATA will not emit INSERT statements. SIMPLE does not use multi-row insert statements. COLUMNS includes column name lists into insert statements. If the DROP option is specified, drop statements are created for tables, views, and sequences. If the block size is set, CLOB and BLOB values larger than this size are split into separate blocks. BLOCKSIZE is used when writing out LOB data, and specifies the point at the values transition from being inserted as inline values, to be inserted using out-of-line commands. NOSETTINGS turns off dumping the database settings (the SET XXX commands)
If no 'TO fileName' clause is specified, the script is returned as a result set. This command can be used to create a backup of the database. For long term storage, it is more portable than copying the database files.
If a 'TO fileName' clause is specified, then the whole script (including insert statements) is written to this file, and a result set without the insert statements is returned.
The password must be in single quotes; it is case sensitive and can contain spaces.
This command locks objects while it is running. Admin rights are required to execute this command.
When using the TABLE or SCHEMA option, only the selected table(s) / schema(s) are included.
Example:
SCRIPT NODATA
SHOW
SHOW |
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Lists the schemas, tables, or the columns of a table.
Example:
SHOW TABLES
Explicit table
TABLE |
| tableName |
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Selects data from a table.
This command is an equivalent to SELECT * FROM tableName. See SELECT command for description of ORDER BY, OFFSET, and FETCH.
Example:
TABLE TEST;
TABLE TEST ORDER BY ID FETCH FIRST ROW ONLY;
Table value
VALUES rowValueExpression |
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A list of rows that can be used like a table. See See SELECT command for description of ORDER BY, OFFSET, and FETCH. The column list of the resulting table is C1, C2, and so on.
Example:
VALUES (1, 'Hello'), (2, 'World');
WITH
Can be used to create a recursive or non-recursive query (common table expression). For recursive queries the first select has to be a UNION. One or more common table entries can be referred to by name. Column name declarations are optional - the column names will be inferred from the named select queries.
Example:
WITH RECURSIVE cte(n) AS (
SELECT 1
UNION ALL
SELECT n + 1
FROM cte
WHERE n < 100
)
SELECT sum(n) FROM cte;
Example 2:
WITH cte1 AS (
SELECT 1 AS FIRST_COLUMN
), cte2 AS (
SELECT FIRST_COLUMN+1 AS FIRST_COLUMN FROM cte1
)
SELECT sum(FIRST_COLUMN) FROM cte2;
Commands (Data Definition)
ALTER DOMAIN
ALTER DOMAIN |
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Changes the default or on update expression of a domain. Schema owner rights are required to execute this command.
SET DEFAULT changes the default expression of a domain.
DROP DEFAULT removes the default expression of a domain. Old expression is copied into domains and columns that use this domain and don't have an own default expression.
SET ON UPDATE changes the expression that is set on update if value for this domain is not specified in update statement.
DROP ON UPDATE removes the expression that is set on update of a column with this domain. Old expression is copied into domains and columns that use this domain and don't have an own on update expression.
This command commits an open transaction in this connection.
Example:
ALTER DOMAIN D1 SET DEFAULT '';
ALTER DOMAIN D1 DROP DEFAULT;
ALTER DOMAIN D1 SET ON UPDATE CURRENT_TIMESTAMP;
ALTER DOMAIN D1 DROP ON UPDATE;
ALTER DOMAIN ADD CONSTRAINT
ALTER DOMAIN |
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| domainName |
ADD |
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CHECK ( condition ) |
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Adds a constraint to a domain. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER DOMAIN D ADD CONSTRAINT D_POSITIVE CHECK (VALUE > 0)
ALTER DOMAIN DROP CONSTRAINT
Removes a constraint from a domain. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER DOMAIN D DROP CONSTRAINT D_POSITIVE
ALTER DOMAIN RENAME
ALTER DOMAIN |
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| domainName RENAME TO newName |
Renames a domain. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER DOMAIN TEST RENAME TO MY_TYPE
ALTER DOMAIN RENAME CONSTRAINT
Renames a constraint. This command commits an open transaction in this connection.
Example:
ALTER DOMAIN D RENAME CONSTRAINT FOO TO BAR
ALTER INDEX RENAME
ALTER INDEX |
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| indexName RENAME TO newIndexName |
Renames an index. This command commits an open transaction in this connection.
Example:
ALTER INDEX IDXNAME RENAME TO IDX_TEST_NAME
ALTER SCHEMA RENAME
ALTER SCHEMA |
| schemaName RENAME TO newSchemaName |
Renames a schema. Schema admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER SCHEMA TEST RENAME TO PRODUCTION
ALTER SEQUENCE
ALTER SEQUENCE |
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Changes the parameters of a sequence. Schema owner rights are required to execute this command. This command does not commit the current transaction; however the new value is used by other transactions immediately, and rolling back this command has no effect.
Example:
ALTER SEQUENCE SEQ_ID RESTART WITH 1000
ALTER TABLE ADD
ALTER TABLE |
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FIRST |
Adds a new column to a table. This command commits an open transaction in this connection.
If USING is specified the provided expression is used to generate initial value of the new column for each row. The expression may reference existing columns of the table. Otherwise the DEFAULT expression is used, if any. If neither USING nor DEFAULT are specified, the NULL is used.
Example:
ALTER TABLE TEST ADD CREATEDATE TIMESTAMP
ALTER TABLE ADD CONSTRAINT
ALTER TABLE |
| tableName ADD tableConstraintDefinition |
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Adds a constraint to a table. If NOCHECK is specified, existing rows are not checked for consistency (the default is to check consistency for existing rows). The required indexes are automatically created if they don't exist yet. It is not possible to disable checking for unique constraints. This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST ADD CONSTRAINT NAME_UNIQUE UNIQUE(NAME)
ALTER TABLE RENAME CONSTRAINT
Renames a constraint. This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST RENAME CONSTRAINT FOO TO BAR
ALTER TABLE ALTER COLUMN
ALTER TABLE |
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ALTER COLUMN |
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Changes the data type of a column, rename a column, change the identity value, or change the selectivity.
Changing the data type fails if the data can not be converted.
SET GENERATED ALWAYS, SET GENERATED BY DEFAULT, or identity options convert the column into identity column (if it wasn't an identity column) and set new values of specified options for its sequence.
DROP IDENTITY removes identity status of a column.
SELECTIVITY sets the selectivity (1-100) for a column. Setting the selectivity to 0 means the default value. Selectivity is used by the cost based optimizer to calculate the estimated cost of an index. Selectivity 100 means values are unique, 10 means every distinct value appears 10 times on average.
SET DEFAULT changes the default value of a column. This command doesn't affect generated and identity columns.
DROP DEFAULT removes the default value of a column.
DROP EXPRESSION converts generated column into base column.
SET ON UPDATE changes the value that is set on update if value for this column is not specified in update statement. This command doesn't affect generated and identity columns.
DROP ON UPDATE removes the value that is set on update of a column.
SET DEFAULT ON NULL makes NULL value work as DEFAULT value is assignments to this column.
DROP DEFAULT ON NULL makes NULL value work as NULL value in assignments to this column.
SET NOT NULL sets a column to not allow NULL. Rows may not contain NULL in this column.
DROP NOT NULL and SET NULL set a column to allow NULL. The column may not be part of a primary key and may not be an identity column.
SET DATA TYPE changes the data type of a column, for each row old value is converted to this data type unless USING is specified with a custom expression. USING expression may reference previous value of the modified column by its name and values of other columns.
SET INVISIBLE makes the column hidden, i.e. it will not appear in SELECT * results. SET VISIBLE has the reverse effect.
This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST ALTER COLUMN NAME CLOB;
ALTER TABLE TEST ALTER COLUMN NAME RENAME TO TEXT;
ALTER TABLE TEST ALTER COLUMN ID RESTART WITH 10000;
ALTER TABLE TEST ALTER COLUMN NAME SELECTIVITY 100;
ALTER TABLE TEST ALTER COLUMN NAME SET DEFAULT '';
ALTER TABLE TEST ALTER COLUMN NAME SET NOT NULL;
ALTER TABLE TEST ALTER COLUMN NAME SET NULL;
ALTER TABLE TEST ALTER COLUMN NAME SET VISIBLE;
ALTER TABLE TEST ALTER COLUMN NAME SET INVISIBLE;
ALTER TABLE DROP COLUMN
Removes column(s) from a table. This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST DROP COLUMN NAME
ALTER TABLE TEST DROP COLUMN (NAME1, NAME2)
ALTER TABLE DROP CONSTRAINT
ALTER TABLE |
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Removes a constraint or a primary key from a table. If CASCADE is specified, unique or primary key constraint is dropped together with all referential constraints that reference the specified constraint. This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST DROP CONSTRAINT UNIQUE_NAME RESTRICT
ALTER TABLE SET
Disables or enables referential integrity checking for a table. This command can be used inside a transaction. Enabling referential integrity does not check existing data, except if CHECK is specified. Use SET REFERENTIAL_INTEGRITY to disable it for all tables; the global flag and the flag for each table are independent.
This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST SET REFERENTIAL_INTEGRITY FALSE
ALTER TABLE RENAME
ALTER TABLE |
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| tableName RENAME TO newName |
Renames a table. This command commits an open transaction in this connection.
Example:
ALTER TABLE TEST RENAME TO MY_DATA
ALTER USER ADMIN
ALTER USER userName ADMIN |
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Switches the admin flag of a user on or off.
Only unquoted or uppercase user names are allowed. Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER USER TOM ADMIN TRUE
ALTER USER RENAME
ALTER USER userName RENAME TO newUserName |
Renames a user. After renaming a user, the password becomes invalid and needs to be changed as well.
Only unquoted or uppercase user names are allowed. Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER USER TOM RENAME TO THOMAS
ALTER USER SET PASSWORD
Changes the password of a user. Only unquoted or uppercase user names are allowed. The password must be enclosed in single quotes. It is case sensitive and can contain spaces. The salt and hash values are hex strings.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER USER SA SET PASSWORD 'rioyxlgt'
ALTER VIEW RECOMPILE
ALTER VIEW |
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| viewName RECOMPILE |
Recompiles a view after the underlying tables have been changed or created. Schema owner rights are required to execute this command. This command is used for views created using CREATE FORCE VIEW. This command commits an open transaction in this connection.
Example:
ALTER VIEW ADDRESS_VIEW RECOMPILE
ALTER VIEW RENAME
ALTER VIEW |
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| viewName RENAME TO newName |
Renames a view. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
ALTER VIEW TEST RENAME TO MY_VIEW
ANALYZE
ANALYZE |
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Updates the selectivity statistics of tables. If no table name is given, all tables are analyzed. The selectivity is used by the cost based optimizer to select the best index for a given query. If no sample size is set, up to 10000 rows per table are read. The value 0 means all rows are read. The selectivity can be set manually using ALTER TABLE ALTER COLUMN SELECTIVITY. Manual values are overwritten by this statement. The selectivity is available in the INFORMATION_SCHEMA.COLUMNS table.
This command commits an open transaction in this connection.
Example:
ANALYZE SAMPLE_SIZE 1000
COMMENT ON
COMMENT ON |
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IS expression |
Sets the comment of a database object. Use NULL or empty string to remove the comment.
Admin rights are required to execute this command if object is a USER or ROLE. Schema owner rights are required to execute this command for all other types of objects. This command commits an open transaction in this connection.
Example:
COMMENT ON TABLE TEST IS 'Table used for testing'
CREATE AGGREGATE
CREATE AGGREGATE |
|
| aggregateName FOR classNameString |
Creates a new user-defined aggregate function. The method name must be the full qualified class name. The class must implement the interface org.h2.api.Aggregate or org.h2.api.AggregateFunction.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
CREATE AGGREGATE SIMPLE_MEDIAN FOR 'com.acme.db.Median'
CREATE ALIAS
Creates a new function alias. If this is a ResultSet returning function, by default the return value is cached in a local temporary file.
DETERMINISTIC - Deterministic functions must always return the same value for the same parameters.
The method name must be the full qualified class and method name, and may optionally include the parameter classes as in java.lang.Integer.parseInt(java.lang.String, int). The class and the method must both be public, and the method must be static. The class must be available in the classpath of the database engine (when using the server mode, it must be in the classpath of the server).
When defining a function alias with source code, the Sun javac is compiler is used if the file tools.jar is in the classpath. If not, javac is run as a separate process. Only the source code is stored in the database; the class is compiled each time the database is re-opened. Source code is usually passed as dollar quoted text to avoid escaping problems. If import statements are used, then the tag @CODE must be added before the method.
If the method throws an SQLException, it is directly re-thrown to the calling application; all other exceptions are first converted to a SQLException.
If the first parameter of the Java function is a java.sql.Connection, then a connection to the database is provided. This connection must not be closed. If the class contains multiple methods with the given name but different parameter count, all methods are mapped.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
If you have the Groovy jar in your classpath, it is also possible to write methods using Groovy.
Example:
CREATE ALIAS MY_SQRT FOR 'java.lang.Math.sqrt';
CREATE ALIAS MY_ROUND FOR 'java.lang.Math.round(double)';
CREATE ALIAS GET_SYSTEM_PROPERTY FOR 'java.lang.System.getProperty';
CALL GET_SYSTEM_PROPERTY('java.class.path');
CALL GET_SYSTEM_PROPERTY('com.acme.test', 'true');
CREATE ALIAS REVERSE AS 'String reverse(String s) { return new StringBuilder(s).reverse().toString(); }';
CALL REVERSE('Test');
CREATE ALIAS tr AS '@groovy.transform.CompileStatic
static String tr(String str, String sourceSet, String replacementSet){
return str.tr(sourceSet, replacementSet);
}
'
CREATE CONSTANT
Creates a new constant. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
CREATE CONSTANT ONE VALUE 1
CREATE DOMAIN
CREATE DOMAIN |
|
| domainName |
| dataTypeOrDomain |
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Creates a new domain to define a set of permissible values. Schema owner rights are required to execute this command. Domains can be used as data types. The domain constraints must evaluate to TRUE or to UNKNOWN. In the conditions, the term VALUE refers to the value being tested.
This command commits an open transaction in this connection.
Example:
CREATE DOMAIN EMAIL AS VARCHAR(255) CHECK (POSITION('@', VALUE) > 1)
CREATE INDEX
CREATE |
| INDEX |
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ON |
| tableName ( indexColumn |
| ) |
|
Creates a new index. This command commits an open transaction in this connection.
INCLUDE clause may only be specified for UNIQUE indexes. With this clause additional columns are included into index, but aren't used in unique checks. If nulls distinct clause is not specified, the default is NULLS DISTINCT, excluding some compatibility modes.
Spatial indexes are supported only on GEOMETRY columns. They may contain only one column and are used by the spatial overlapping operator.
Example:
CREATE INDEX IDXNAME ON TEST(NAME)
CREATE LINKED TABLE
CREATE |
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LINKED TABLE |
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tableName ( driverString , urlString , userString , passwordString , |
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Creates a table link to an external table. The driver name may be empty if the driver is already loaded. If the schema name is not set, only one table with that name may exist in the target database.
FORCE - Create the LINKED TABLE even if the remote database/table does not exist.
EMIT UPDATES - Usually, for update statements, the old rows are deleted first and then the new rows are inserted. It is possible to emit update statements (except on rollback), however in this case multi-row unique key updates may not always work. Linked tables to the same database share one connection.
READONLY - is set, the remote table may not be updated. This is enforced by H2.
FETCH_SIZE - the number of rows fetched, a hint with non-negative number of rows to fetch from the external table at once, may be ignored by the driver of external database. 0 is default and means no hint. The value is passed to java.sql.Statement.setFetchSize() method.
AUTOCOMMIT - is set to ON, the auto-commit mode is enable. OFF is disable. The value is passed to java.sql.Connection.setAutoCommit() method.
If the connection to the source database is lost, the connection is re-opened (this is a workaround for MySQL that disconnects after 8 hours of inactivity by default).
If a query is used instead of the original table name, the table is read only. Queries must be enclosed in parenthesis: (SELECT * FROM ORDERS).
To use JNDI to get the connection, the driver class must be a javax.naming.Context (for example javax.naming.InitialContext), and the URL must be the resource name (for example java:comp/env/jdbc/Test).
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
CREATE LINKED TABLE LINK('org.h2.Driver', 'jdbc:h2:./test2',
'sa', 'sa', 'TEST');
CREATE LINKED TABLE LINK('', 'jdbc:h2:./test2', 'sa', 'sa',
'(SELECT * FROM TEST WHERE ID>0)');
CREATE LINKED TABLE LINK('javax.naming.InitialContext',
'java:comp/env/jdbc/Test', NULL, NULL,
'(SELECT * FROM TEST WHERE ID>0)');
CREATE ROLE
CREATE ROLE |
| newRoleName |
Creates a new role. This command commits an open transaction in this connection.
Example:
CREATE ROLE READONLY
CREATE SCHEMA
CREATE SCHEMA |
|
| |||||||||||
|
|
Creates a new schema. Schema admin rights are required to execute this command.
If schema name is not specified, the owner name is used as a schema name. If schema name is specified, but no owner is specified, the current user is used as an owner.
Schema owners can create, rename, and drop objects in the schema. Schema owners can drop the schema itself, but cannot rename it. Some objects may still require admin rights for their creation, see documentation of their CREATE statements for details.
Optional table engine parameters are used when CREATE TABLE command is run on this schema without having its engine params set.
This command commits an open transaction in this connection.
Example:
CREATE SCHEMA TEST_SCHEMA AUTHORIZATION SA
CREATE SEQUENCE
Creates a new sequence. Schema owner rights are required to execute this command.
The data type of a sequence must be a numeric type, the default is BIGINT. Sequence can produce only integer values. For TINYINT the allowed values are between -128 and 127. For SMALLINT the allowed values are between -32768 and 32767. For INTEGER the allowed values are between -2147483648 and 2147483647. For BIGINT the allowed values are between -9223372036854775808 and 9223372036854775807. For NUMERIC and DECFLOAT the allowed values depend on precision, but cannot exceed the range of BIGINT data type (from -9223372036854775808 to 9223372036854775807); the scale of NUMERIC must be 0. For REAL the allowed values are between -16777216 and 16777216. For DOUBLE PRECISION the allowed values are between -9007199254740992 and 9007199254740992.
Used values are never re-used, even when the transaction is rolled back.
This command commits an open transaction in this connection.
Example:
CREATE SEQUENCE SEQ_ID;
CREATE SEQUENCE SEQ2 AS INTEGER START WITH 10;
CREATE TABLE
CREATE |
|
|
TABLE |
|
| tableName |
|
|
|
|
|
|
Creates a new table.
Admin rights are required to execute this command if and only if ENGINE option is used or custom default table engine is configured in the database. Schema owner rights or ALTER ANY SCHEMA rights are required for creation of regular tables and GLOBAL TEMPORARY tables.
Cached tables (the default for regular tables) are persistent, and the number of rows is not limited by the main memory. Memory tables (the default for temporary tables) are persistent, but the index data is kept in main memory, that means memory tables should not get too large.
Temporary tables are deleted when closing or opening a database. Temporary tables can be global (accessible by all connections) or local (only accessible by the current connection). The default for temporary tables is global. Indexes of temporary tables are kept fully in main memory, unless the temporary table is created using CREATE CACHED TABLE.
The ENGINE option is only required when custom table implementations are used. The table engine class must implement the interface org.h2.api.TableEngine. Any table engine parameters are passed down in the tableEngineParams field of the CreateTableData object.
Either ENGINE, or WITH (table engine params), or both may be specified. If ENGINE is not specified in CREATE TABLE, then the engine specified by DEFAULT_TABLE_ENGINE option of database params is used.
Tables with the NOT PERSISTENT modifier are kept fully in memory, and all rows are lost when the database is closed.
The column definitions are optional if a query is specified. In that case the column list of the query is used. If the query is specified its results are inserted into created table unless WITH NO DATA is specified.
This command commits an open transaction, except when using TRANSACTIONAL (only supported for temporary tables).
Example:
CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR(255))
CREATE TRIGGER
CREATE TRIGGER |
|
| triggerName |
BEFORE | |||
AFTER | |||
|
INSERT | ||||||||
UPDATE | ||||||||
DELETE | ||||||||
|
| ON |
| tableName |
|
|
|
Creates a new trigger. Admin rights are required to execute this command.
The trigger class must be public and implement org.h2.api.Trigger. Inner classes are not supported. The class must be available in the classpath of the database engine (when using the server mode, it must be in the classpath of the server).
The sourceCodeString must define a single method with no parameters that returns org.h2.api.Trigger. See CREATE ALIAS for requirements regarding the compilation. Alternatively, javax.script.ScriptEngineManager can be used to create an instance of org.h2.api.Trigger. Currently JavaScript (included in older JREs or provided by org.graalvm.js:js-scriptengine library in newer JREs) and ruby (with JRuby) are supported. In that case the source must begin respectively with //javascript or #ruby.
BEFORE triggers are called after data conversion is made, default values are set, null and length constraint checks have been made; but before other constraints have been checked. If there are multiple triggers, the order in which they are called is undefined.
ROLLBACK can be specified in combination with INSERT, UPDATE, and DELETE. Only row based AFTER trigger can be called on ROLLBACK. Exceptions that occur within such triggers are ignored. As the operations that occur within a trigger are part of the transaction, ROLLBACK triggers are only required if an operation communicates outside of the database.
INSTEAD OF triggers are implicitly row based and behave like BEFORE triggers. Only the first such trigger is called. Such triggers on views are supported. They can be used to make views updatable. These triggers on INSERT and UPDATE must update the passed new row to values that were actually inserted by the trigger; they are used for FINAL TABLE and for retrieval of generated keys.
A BEFORE SELECT trigger is fired just before the database engine tries to read from the table. The trigger can be used to update a table on demand. The trigger is called with both 'old' and 'new' set to null.
The MERGE statement will call both INSERT and UPDATE triggers. Not supported are SELECT triggers with the option FOR EACH ROW, and AFTER SELECT triggers.
Committing or rolling back a transaction within a trigger is not allowed, except for SELECT triggers.
By default a trigger is called once for each statement, without the old and new rows. FOR EACH ROW triggers are called once for each inserted, updated, or deleted row.
QUEUE is implemented for syntax compatibility with HSQL and has no effect.
The trigger need to be created in the same schema as the table. The schema name does not need to be specified when creating the trigger.
This command commits an open transaction in this connection.
Example:
CREATE TRIGGER TRIG_INS BEFORE INSERT ON TEST FOR EACH ROW CALL 'MyTrigger';
CREATE TRIGGER TRIG_SRC BEFORE INSERT ON TEST AS
'org.h2.api.Trigger create() { return new MyTrigger("constructorParam"); }';
CREATE TRIGGER TRIG_JS BEFORE INSERT ON TEST AS '//javascript
return new (Java.type("org.example.MyTrigger"))("constructorParam");';
CREATE TRIGGER TRIG_RUBY BEFORE INSERT ON TEST AS '#ruby
Java::MyPackage::MyTrigger.new("constructorParam")';
CREATE USER
Creates a new user. For compatibility, only unquoted or uppercase user names are allowed. The password must be in single quotes. It is case sensitive and can contain spaces. The salt and hash values are hex strings.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
CREATE USER GUEST PASSWORD 'abc'
CREATE VIEW
Creates a new view. If the force option is used, then the view is created even if the underlying table(s) don't exist. Schema owner rights are required to execute this command.
If the OR REPLACE clause is used an existing view will be replaced, and any dependent views will not need to be recreated. If dependent views will become invalid as a result of the change an error will be generated, but this error can be ignored if the FORCE clause is also used.
Views are not updatable except when using 'instead of' triggers.
This command commits an open transaction in this connection.
Example:
CREATE VIEW TEST_VIEW AS SELECT * FROM TEST WHERE ID < 100
CREATE MATERIALIZED VIEW
Creates a new materialized view. Schema owner rights are required to execute this command.
If the OR REPLACE clause is used an existing view will be replaced.
Views are not updatable except using REFRESH MATERIALIZED VIEW.
This command commits an open transaction in this connection.
Example:
CREATE MATERIALIZED VIEW TEST_VIEW AS SELECT * FROM TEST WHERE ID < 100
DROP AGGREGATE
DROP AGGREGATE |
| aggregateName |
Drops an existing user-defined aggregate function. Schema owner rights are required to execute this command.
This command commits an open transaction in this connection.
Example:
DROP AGGREGATE SIMPLE_MEDIAN
DROP ALIAS
DROP ALIAS |
|
| aliasName |
Drops an existing function alias. Schema owner rights are required to execute this command.
This command commits an open transaction in this connection.
Example:
DROP ALIAS MY_SQRT
DROP ALL OBJECTS
DROP ALL OBJECTS |
|
Drops all existing views, tables, sequences, schemas, function aliases, roles, user-defined aggregate functions, domains, and users (except the current user). If DELETE FILES is specified, the database files will be removed when the last user disconnects from the database. Warning: this command can not be rolled back.
Admin rights are required to execute this command.
Example:
DROP ALL OBJECTS
DROP CONSTANT
DROP CONSTANT |
|
| constantName |
Drops a constant. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
DROP CONSTANT ONE
DROP DOMAIN
DROP DOMAIN |
|
| domainName |
|
Drops a data type (domain). Schema owner rights are required to execute this command.
The command will fail if it is referenced by a column or another domain (the default). Column descriptors are replaced with original definition of specified domain if the CASCADE clause is used. Default and on update expressions are copied into domains and columns that use this domain and don't have own expressions. Domain constraints are copied into domains that use this domain and to columns (as check constraints) that use this domain. This command commits an open transaction in this connection.
Example:
DROP DOMAIN EMAIL
DROP INDEX
DROP INDEX |
|
| indexName |
Drops an index. This command commits an open transaction in this connection.
Example:
DROP INDEX IF EXISTS IDXNAME
DROP ROLE
DROP ROLE |
| roleName |
Drops a role. Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
DROP ROLE READONLY
DROP SCHEMA
DROP SCHEMA |
| schemaName |
|
Drops a schema. Schema owner rights are required to execute this command. The command will fail if objects in this schema exist and the RESTRICT clause is used (the default). All objects in this schema are dropped as well if the CASCADE clause is used. This command commits an open transaction in this connection.
Example:
DROP SCHEMA TEST_SCHEMA
DROP SEQUENCE
DROP SEQUENCE |
|
| sequenceName |
Drops a sequence. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
DROP SEQUENCE SEQ_ID
DROP TABLE
Drops an existing table, or a list of tables. The command will fail if dependent objects exist and the RESTRICT clause is used (the default). All dependent views and constraints are dropped as well if the CASCADE clause is used. This command commits an open transaction in this connection.
Example:
DROP TABLE TEST
DROP TRIGGER
DROP TRIGGER |
|
| triggerName |
Drops an existing trigger. This command commits an open transaction in this connection.
Example:
DROP TRIGGER TRIG_INS
DROP USER
DROP USER |
| userName |
Drops a user. The current user cannot be dropped. For compatibility, only unquoted or uppercase user names are allowed.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
DROP USER TOM
DROP VIEW
DROP VIEW |
|
| viewName |
|
Drops an existing view. Schema owner rights are required to execute this command. All dependent views are dropped as well if the CASCADE clause is used (the default). The command will fail if dependent views exist and the RESTRICT clause is used. This command commits an open transaction in this connection.
Example:
DROP VIEW TEST_VIEW
DROP MATERIALIZED VIEW
DROP MATERIALIZED VIEW |
|
| viewName |
Drops an existing materialized view. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
DROP MATERIALIZED VIEW TEST_VIEW
REFRESH MATERIALIZED VIEW
REFRESH MATERIALIZED VIEW |
|
| viewName |
Recreates an existing materialized view. Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
REFRESH MATERIALIZED VIEW TEST_VIEW
TRUNCATE TABLE
TRUNCATE TABLE |
| tableName |
|
Removes all rows from a table. Unlike DELETE FROM without where clause, this command can not be rolled back. This command is faster than DELETE without where clause. Only regular data tables without foreign key constraints can be truncated (except if referential integrity is disabled for this database or for this table). Linked tables can't be truncated. If RESTART IDENTITY is specified next values for identity columns are restarted.
This command commits an open transaction in this connection.
Example:
TRUNCATE TABLE TEST
Commands (Other)
CHECKPOINT
CHECKPOINTFlushes the data to disk.
Admin rights are required to execute this command.
Example:
CHECKPOINT
CHECKPOINT SYNC
CHECKPOINT SYNC |
Flushes the data to disk and forces all system buffers be written to the underlying device.
Admin rights are required to execute this command.
Example:
CHECKPOINT SYNC
COMMIT
COMMIT |
|
Commits a transaction.
Example:
COMMIT
COMMIT TRANSACTION
COMMIT TRANSACTION transactionName |
Sets the resolution of an in-doubt transaction to 'commit'.
Admin rights are required to execute this command. This command is part of the 2-phase-commit protocol.
Example:
COMMIT TRANSACTION XID_TEST
GRANT RIGHT
GRANT |
| ON |
| |||||||||||||||||||||||||
|
TO |
|
Grants rights for a table to a user or role.
Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
GRANT SELECT ON TEST TO READONLY
GRANT ALTER ANY SCHEMA
GRANT ALTER ANY SCHEMA TO userName |
Grant schema admin rights to a user.
Schema admin can create, rename, or drop schemas and also has schema owner rights in every schema.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
GRANT ALTER ANY SCHEMA TO Bob
GRANT ROLE
Grants a role to a user or role.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
GRANT READONLY TO PUBLIC
HELP
HELP |
|
Displays the help pages of SQL commands or keywords.
Example:
HELP SELECT
PREPARE COMMIT
PREPARE COMMIT newTransactionName |
Prepares committing a transaction. This command is part of the 2-phase-commit protocol.
Example:
PREPARE COMMIT XID_TEST
REVOKE RIGHT
REVOKE |
| ON |
| |||||||||||||||||||||||||
|
FROM |
|
Removes rights for a table from a user or role.
Schema owner rights are required to execute this command. This command commits an open transaction in this connection.
Example:
REVOKE SELECT ON TEST FROM READONLY
REVOKE ALTER ANY SCHEMA
REVOKE ALTER ANY SCHEMA FROM userName |
Removes schema admin rights from a user.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
GRANT ALTER ANY SCHEMA TO Bob
REVOKE ROLE
Removes a role from a user or role.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
REVOKE READONLY FROM TOM
ROLLBACK
ROLLBACK |
|
|
Rolls back a transaction. If a savepoint name is used, the transaction is only rolled back to the specified savepoint.
Example:
ROLLBACK
ROLLBACK TRANSACTION
ROLLBACK TRANSACTION transactionName |
Sets the resolution of an in-doubt transaction to 'rollback'.
Admin rights are required to execute this command. This command is part of the 2-phase-commit protocol.
Example:
ROLLBACK TRANSACTION XID_TEST
SAVEPOINT
SAVEPOINT savepointName |
Create a new savepoint. See also ROLLBACK. Savepoints are only valid until the transaction is committed or rolled back.
Example:
SAVEPOINT HALF_DONE
SET @
SET @variableName |
| expression |
Updates a user-defined variable. Variables are not persisted and session scoped, that means only visible from within the session in which they are defined. This command does not commit a transaction, and rollback does not affect it.
Example:
SET @TOTAL=0
SET ALLOW_LITERALS
SET ALLOW_LITERALS |
|
This setting can help solve the SQL injection problem. By default, text and number literals are allowed in SQL statements. However, this enables SQL injection if the application dynamically builds SQL statements. SQL injection is not possible if user data is set using parameters ('?').
NONE means literals of any kind are not allowed, only parameters and constants are allowed. NUMBERS mean only numerical and boolean literals are allowed. ALL means all literals are allowed (default).
See also CREATE CONSTANT.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;ALLOW_LITERALS=NONE
Example:
SET ALLOW_LITERALS NONE
SET AUTOCOMMIT
SET AUTOCOMMIT |
|
Switches auto commit on or off. This setting can be appended to the database URL: jdbc:h2:./test;AUTOCOMMIT=OFF - however this will not work as expected when using a connection pool (the connection pool manager will re-enable autocommit when returning the connection to the pool, so autocommit will only be disabled the first time the connection is used.
Example:
SET AUTOCOMMIT OFF
SET CACHE_SIZE
SET CACHE_SIZE int |
Sets the size of the cache in KB (each KB being 1024 bytes) for the current database. The default is 65536 per available GB of RAM, i.e. 64 MB per GB. The value is rounded to the next higher power of two. Depending on the virtual machine, the actual memory required may be higher.
This setting is persistent and affects all connections as there is only one cache per database. Using a very small value (specially 0) will reduce performance a lot. This setting only affects the database engine (the server in a client/server environment; in embedded mode, the database engine is in the same process as the application). It has no effect for in-memory databases.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;CACHE_SIZE=8192
Example:
SET CACHE_SIZE 8192
SET CLUSTER
SET CLUSTER serverListString |
This command should not be used directly by an application, the statement is executed automatically by the system. The behavior may change in future releases. Sets the cluster server list. An empty string switches off the cluster mode. Switching on the cluster mode requires admin rights, but any user can switch it off (this is automatically done when the client detects the other server is not responding).
This command is effective immediately, but does not commit an open transaction.
Example:
SET CLUSTER ''
SET BUILTIN_ALIAS_OVERRIDE
SET BUILTIN_ALIAS_OVERRIDE |
|
Allows the overriding of the builtin system date/time functions for unit testing purposes.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
SET BUILTIN_ALIAS_OVERRIDE TRUE
SET CATALOG
SET CATALOG |
|
This command has no effect if the specified name matches the name of the database, otherwise it throws an exception.
This command does not commit a transaction.
Example:
SET CATALOG 'DB'
SET CATALOG DB_NAME
SET COLLATION
Sets the collation used for comparing strings. This command can only be executed if there are no tables defined. See java.text.Collator for details about the supported collations and the STRENGTH (PRIMARY is usually case- and umlaut-insensitive; SECONDARY is case-insensitive but umlaut-sensitive; TERTIARY is both case- and umlaut-sensitive; IDENTICAL is sensitive to all differences and only affects ordering).
The ICU4J collator is used if it is in the classpath. It is also used if the collation name starts with ICU4J_ (in that case, the ICU4J must be in the classpath, otherwise an exception is thrown). The default collator is used if the collation name starts with DEFAULT_ (even if ICU4J is in the classpath). The charset collator is used if the collation name starts with CHARSET_ (e.g. CHARSET_CP500). This collator sorts strings according to the binary representation in the given charset.
Admin rights are required to execute this command. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;COLLATION='ENGLISH'
Example:
SET COLLATION ENGLISH
SET COLLATION CHARSET_CP500
SET DATABASE_EVENT_LISTENER
SET DATABASE_EVENT_LISTENER classNameString |
Sets the event listener class. An empty string ('') means no listener should be used. This setting is not persistent.
Admin rights are required to execute this command, except if it is set when opening the database (in this case it is reset just after opening the database). This setting can be appended to the database URL: jdbc:h2:./test;DATABASE_EVENT_LISTENER='sample.MyListener'
Example:
SET DATABASE_EVENT_LISTENER 'sample.MyListener'
SET DB_CLOSE_DELAY
SET DB_CLOSE_DELAY int |
Sets the delay for closing a database if all connections are closed. The value -1 means the database is never closed until the close delay is set to some other value or SHUTDOWN is called. The value 0 means no delay (default; the database is closed if the last connection to it is closed). Values 1 and larger mean the number of seconds the database is left open after closing the last connection.
If the application exits normally or System.exit is called, the database is closed immediately, even if a delay is set.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;DB_CLOSE_DELAY=-1
Example:
SET DB_CLOSE_DELAY -1
SET DEFAULT_LOCK_TIMEOUT
SET DEFAULT LOCK_TIMEOUT int |
Sets the default lock timeout (in milliseconds) in this database that is used for the new sessions. The default value for this setting is 1000 (one second).
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent.
Example:
SET DEFAULT_LOCK_TIMEOUT 5000
SET DEFAULT_NULL_ORDERING
SET DEFAULT_NULL_ORDERING |
|
Changes the default ordering of NULL values. This setting affects new indexes without explicit NULLS FIRST or NULLS LAST columns, and ordering clauses of other commands without explicit null ordering. This setting doesn't affect ordering of NULL values inside ARRAY or ROW values (ARRAY[NULL] is always considered as smaller than ARRAY[1] during sorting).
LOW is the default one, NULL values are considered as smaller than other values during sorting.
With HIGH default ordering NULL values are considered as larger than other values during sorting.
With FIRST default ordering NULL values are sorted before other values, no matter if ascending or descending order is used.
With LAST default ordering NULL values are sorted after other values, no matter if ascending or descending order is used.
Please note that FIRST and LAST make impossible to use an index on (A ASC) for ORDER BY A DESC if column is nullable.
This setting is not persistent, but indexes are persisted with explicit NULLS FIRST or NULLS LAST ordering and aren't affected by changes in this setting. Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting can be appended to the database URL: jdbc:h2:./test;DEFAULT_NULL_ORDERING=HIGH
Example:
SET DEFAULT_NULL_ORDERING HIGH
SET DEFAULT_TABLE_TYPE
SET DEFAULT_TABLE_TYPE |
|
Sets the default table storage type that is used when creating new tables. Memory tables are kept fully in the main memory (including indexes), however the data is still stored in the database file. The size of memory tables is limited by the memory. The default is CACHED.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. It has no effect for in-memory databases.
Example:
SET DEFAULT_TABLE_TYPE MEMORY
SET EXCLUSIVE
SET EXCLUSIVE |
|
Switched the database to exclusive mode (1, 2) and back to normal mode (0).
In exclusive mode, new connections are rejected, and operations by other connections are paused until the exclusive mode is disabled. When using the value 1, existing connections stay open. When using the value 2, all existing connections are closed (and current transactions are rolled back) except the connection that executes SET EXCLUSIVE. Only the connection that set the exclusive mode can disable it. When the connection is closed, it is automatically disabled.
Admin rights are required to execute this command. This command commits an open transaction in this connection.
Example:
SET EXCLUSIVE 1
SET IGNORECASE
SET IGNORECASE |
|
If IGNORECASE is enabled, text columns in newly created tables will be case-insensitive. Already existing tables are not affected. The effect of case-insensitive columns is similar to using a collation with strength PRIMARY. Case-insensitive columns are compared faster than when using a collation. String literals and parameters are however still considered case sensitive even if this option is set.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;IGNORECASE=TRUE
Example:
SET IGNORECASE TRUE
SET IGNORE_CATALOGS
SET IGNORE_CATALOGS |
|
If IGNORE_CATALOGS is enabled, catalog names in front of schema names will be ignored. This can be used if multiple catalogs used by the same connections must be simulated. Caveat: if both catalogs contain schemas of the same name and if those schemas contain objects of the same name, this will lead to errors, when trying to manage, access or change these objects. This setting can be appended to the database URL: jdbc:h2:./test;IGNORE_CATALOGS=TRUE
Example:
SET IGNORE_CATALOGS TRUE
SET JAVA_OBJECT_SERIALIZER
Sets the object used to serialize and deserialize java objects being stored in column of type OTHER. The serializer class must be public and implement org.h2.api.JavaObjectSerializer. Inner classes are not supported. The class must be available in the classpath of the database engine (when using the server mode, it must be both in the classpath of the server and the client). This command can only be executed if there are no tables defined.
Admin rights are required to execute this command. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;JAVA_OBJECT_SERIALIZER='com.acme.SerializerClassName'
Example:
SET JAVA_OBJECT_SERIALIZER 'com.acme.SerializerClassName'
SET LAZY_QUERY_EXECUTION
SET LAZY_QUERY_EXECUTION int |
Sets the lazy query execution mode. The values 0, 1 are supported.
If true, then large results are retrieved in chunks.
Note that not all queries support this feature, queries which do not are processed normally.
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;LAZY_QUERY_EXECUTION=1
Example:
SET LAZY_QUERY_EXECUTION 1
SET LOCK_MODE
SET LOCK_MODE int |
Sets the lock mode. The values 0, 1, 2, and 3 are supported. The default is 3. This setting affects all connections.
The value 0 means no locking (should only be used for testing). Please note that using SET LOCK_MODE 0 while at the same time using multiple connections may result in inconsistent transactions.
The value 3 means row-level locking for write operations.
The values 1 and 2 have the same effect as 3.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;LOCK_MODE=0
Example:
SET LOCK_MODE 0
SET LOCK_TIMEOUT
SET LOCK_TIMEOUT int |
Sets the lock timeout (in milliseconds) for the current session. The default value for this setting is 1000 (one second).
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;LOCK_TIMEOUT=10000
Example:
SET LOCK_TIMEOUT 1000
SET MAX_LENGTH_INPLACE_LOB
SET MAX_LENGTH_INPLACE_LOB int |
Sets the maximum size of an in-place LOB object.
This is the maximum length of an LOB that is stored with the record itself, and the default value is 256.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent.
Example:
SET MAX_LENGTH_INPLACE_LOB 128
SET MAX_LOG_SIZE
SET MAX_LOG_SIZE int |
Sets the maximum size of the transaction log, in megabytes. If the log is larger, and if there is no open transaction, the transaction log is truncated. If there is an open transaction, the transaction log will continue to grow however. The default max size is 16 MB. This setting has no effect for in-memory databases.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent.
Example:
SET MAX_LOG_SIZE 2
SET MAX_MEMORY_ROWS
SET MAX_MEMORY_ROWS int |
The maximum number of rows in a result set that are kept in-memory. If more rows are read, then the rows are buffered to disk. The default is 40000 per GB of available RAM.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. It has no effect for in-memory databases.
Example:
SET MAX_MEMORY_ROWS 1000
SET MAX_MEMORY_UNDO
SET MAX_MEMORY_UNDO int |
The maximum number of undo records per a session that are kept in-memory. If a transaction is larger, the records are buffered to disk. The default value is 50000. Changes to tables without a primary key can not be buffered to disk. This setting is not supported when using multi-version concurrency.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. It has no effect for in-memory databases.
Example:
SET MAX_MEMORY_UNDO 1000
SET MAX_OPERATION_MEMORY
SET MAX_OPERATION_MEMORY int |
Sets the maximum memory used for large operations (delete and insert), in bytes. Operations that use more memory are buffered to disk, slowing down the operation. The default max size is 100000. 0 means no limit.
This setting is not persistent. Admin rights are required to execute this command, as it affects all connections. It has no effect for in-memory databases. This setting can be appended to the database URL: jdbc:h2:./test;MAX_OPERATION_MEMORY=10000
Example:
SET MAX_OPERATION_MEMORY 0
SET MODE
SET MODE |
|
Changes to another database compatibility mode. For details, see Compatibility Modes.
This setting is not persistent. Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting can be appended to the database URL: jdbc:h2:./test;MODE=MYSQL
Example:
SET MODE HSQLDB
SET NON_KEYWORDS
SET NON_KEYWORDS |
|
Converts the specified tokens from keywords to plain identifiers for the current session. This setting may break some commands and should be used with caution and only when necessary. Use quoted identifiers instead of this setting if possible.
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;NON_KEYWORDS=KEY,VALUE
Example:
SET NON_KEYWORDS KEY, VALUE
SET OPTIMIZE_REUSE_RESULTS
SET OPTIMIZE_REUSE_RESULTS |
|
Enabled (1) or disabled (0) the result reuse optimization. If enabled, subqueries and views used as subqueries are only re-run if the data in one of the tables was changed. This option is enabled by default.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting can be appended to the database URL: jdbc:h2:./test;OPTIMIZE_REUSE_RESULTS=0
Example:
SET OPTIMIZE_REUSE_RESULTS 0
SET PASSWORD
SET PASSWORD string |
Changes the password of the current user. The password must be in single quotes. It is case sensitive and can contain spaces.
This command commits an open transaction in this connection.
Example:
SET PASSWORD 'abcstzri!.5'
SET QUERY_STATISTICS
SET QUERY_STATISTICS |
|
Disabled or enables query statistics gathering for the whole database. The statistics are reflected in the INFORMATION_SCHEMA.QUERY_STATISTICS meta-table.
This setting is not persistent. This command commits an open transaction in this connection. Admin rights are required to execute this command, as it affects all connections.
Example:
SET QUERY_STATISTICS FALSE
SET QUERY_STATISTICS_MAX_ENTRIES
SET QUERY_STATISTICS int |
Set the maximum number of entries in query statistics meta-table. Default value is 100.
This setting is not persistent. This command commits an open transaction in this connection. Admin rights are required to execute this command, as it affects all connections.
Example:
SET QUERY_STATISTICS_MAX_ENTRIES 500
SET QUERY_TIMEOUT
SET QUERY_TIMEOUT int |
Set the query timeout of the current session to the given value. The timeout is in milliseconds. All kinds of statements will throw an exception if they take longer than the given value. The default timeout is 0, meaning no timeout.
This command does not commit a transaction, and rollback does not affect it.
Example:
SET QUERY_TIMEOUT 10000
SET REFERENTIAL_INTEGRITY
SET REFERENTIAL_INTEGRITY |
|
Disabled or enables referential integrity checking for the whole database. Enabling it does not check existing data. Use ALTER TABLE SET to disable it only for one table.
This setting is not persistent. This command commits an open transaction in this connection. Admin rights are required to execute this command, as it affects all connections.
Example:
SET REFERENTIAL_INTEGRITY FALSE
SET RETENTION_TIME
SET RETENTION_TIME int |
How long to retain old, persisted data, in milliseconds. The default is 45000 (45 seconds), 0 means overwrite data as early as possible. It is assumed that a file system and hard disk will flush all write buffers within this time. Using a lower value might be dangerous, unless the file system and hard disk flush the buffers earlier. To manually flush the buffers, use CHECKPOINT SYNC, however please note that according to various tests this does not always work as expected depending on the operating system and hardware.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting is persistent. This setting can be appended to the database URL: jdbc:h2:./test;RETENTION_TIME=0
Example:
SET RETENTION_TIME 0
SET SALT HASH
Sets the password salt and hash for the current user. The password must be in single quotes. It is case sensitive and can contain spaces.
This command commits an open transaction in this connection.
Example:
SET SALT '00' HASH '1122'
SET SCHEMA
SET SCHEMA |
|
Changes the default schema of the current connection. The default schema is used in statements where no schema is set explicitly. The default schema for new connections is PUBLIC.
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;SCHEMA=ABC
Example:
SET SCHEMA 'PUBLIC'
SET SCHEMA INFORMATION_SCHEMA
SET SCHEMA_SEARCH_PATH
SET SCHEMA_SEARCH_PATH schemaName |
|
Changes the schema search path of the current connection. The default schema is used in statements where no schema is set explicitly. The default schema for new connections is PUBLIC.
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;SCHEMA_SEARCH_PATH=ABC,DEF
Example:
SET SCHEMA_SEARCH_PATH INFORMATION_SCHEMA, PUBLIC
SET SESSION CHARACTERISTICS
SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL |
| |||
| |||
| |||
SERIALIZABLE |
Changes the transaction isolation level of the current session. The actual support of isolation levels depends on the database engine.
This command commits an open transaction in this session.
Example:
SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL SERIALIZABLE
SET THROTTLE
SET THROTTLE int |
Sets the throttle for the current connection. The value is the number of milliseconds delay after each 50 ms. The default value is 0 (throttling disabled).
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;THROTTLE=50
Example:
SET THROTTLE 200
SET TIME ZONE
SET TIME ZONE |
|
Sets the current time zone for the session.
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;TIME ZONE='1:00'
Time zone offset used for CURRENT_TIME, CURRENT_TIMESTAMP, CURRENT_DATE, LOCALTIME, and LOCALTIMESTAMP is adjusted, so these functions will return new values based on the same UTC timestamp after execution of this command.
Example:
SET TIME ZONE LOCAL
SET TIME ZONE '-5:00'
SET TIME ZONE INTERVAL '1:00' HOUR TO MINUTE
SET TIME ZONE 'Europe/London'
SET TRACE_LEVEL
SET |
| int |
Sets the trace level for file the file or system out stream. Levels are: 0=off, 1=error, 2=info, 3=debug. The default level is 1 for file and 0 for system out. To use SLF4J, append ;TRACE_LEVEL_FILE=4 to the database URL when opening the database.
This setting is not persistent. Admin rights are required to execute this command, as it affects all connections. This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;TRACE_LEVEL_SYSTEM_OUT=3
Example:
SET TRACE_LEVEL_SYSTEM_OUT 3
SET TRACE_MAX_FILE_SIZE
SET TRACE_MAX_FILE_SIZE int |
Sets the maximum trace file size. If the file exceeds the limit, the file is renamed to .old and a new file is created. If another .old file exists, it is deleted. The default max size is 16 MB.
This setting is persistent. Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting can be appended to the database URL: jdbc:h2:./test;TRACE_MAX_FILE_SIZE=3
Example:
SET TRACE_MAX_FILE_SIZE 10
SET TRUNCATE_LARGE_LENGTH
SET TRUNCATE_LARGE_LENGTH |
|
If TRUE is specified, the CHARACTER, CHARACTER VARYING, VARCHAR_IGNORECASE, BINARY,
Example:
BINARY_VARYING"
SET VARIABLE_BINARY
SET VARIABLE_BINARY |
|
If TRUE is specified, the BINARY data type will be parsed as VARBINARY in the current session. It can be used for compatibility with older versions of H2.
This setting can be appended to the database URL: jdbc:h2:./test;VARIABLE_BINARY=TRUE
Example:
SET VARIABLE_BINARY TRUE
SET WRITE_DELAY
SET WRITE_DELAY int |
Set the maximum delay between a commit and flushing the log, in milliseconds. This setting is persistent. The default is 500 ms.
Admin rights are required to execute this command, as it affects all connections. This command commits an open transaction in this connection. This setting can be appended to the database URL: jdbc:h2:./test;WRITE_DELAY=0
Example:
SET WRITE_DELAY 2000
SHUTDOWN
SHUTDOWN |
|
This statement closes all open connections to the database and closes the database. This command is usually not required, as the database is closed automatically when the last connection to it is closed.
If no option is used, then the database is closed normally. All connections are closed, open transactions are rolled back.
SHUTDOWN COMPACT fully compacts the database (re-creating the database may further reduce the database size). If the database is closed normally (using SHUTDOWN or by closing all connections), then the database is also compacted, but only for at most the time defined by the database setting h2.maxCompactTime in milliseconds (see there).
SHUTDOWN IMMEDIATELY closes the database files without any cleanup and without compacting.
SHUTDOWN DEFRAG is currently equivalent to COMPACT.
Admin rights are required to execute this command.
Example:
SHUTDOWN COMPACT