Package org.h2.api

Interface Trigger

All Known Implementing Classes:

FullText.FullTextTrigger, FullTextLucene.FullTextTrigger, TriggerAdapter

public interface Trigger

A class that implements this interface can be used as a trigger.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DELETE	The trigger is called for DELETE statements.
static final int	INSERT	The trigger is called for INSERT statements.
static final int	SELECT	The trigger is called for SELECT statements.
static final int	UPDATE	The trigger is called for UPDATE statements.

Method Summary

Modifier and Type	Method	Description
default void	close()	This method is called when the database is closed.
void	fire(Connection conn, Object[] oldRow, Object[] newRow)	This method is called for each triggered action.
default void	init(Connection conn, String schemaName, String triggerName, String tableName, boolean before, int type)	This method is called by the database engine once when initializing the trigger.
default void	remove()	This method is called when the trigger is dropped.

Field Details

INSERT

static final int INSERT

The trigger is called for INSERT statements.

See Also:

• Constant Field Values

UPDATE

static final int UPDATE

The trigger is called for UPDATE statements.

See Also:

• Constant Field Values

DELETE

static final int DELETE

The trigger is called for DELETE statements.

See Also:

• Constant Field Values

SELECT

static final int SELECT

The trigger is called for SELECT statements.

See Also:

• Constant Field Values

Method Details

init

default void init(Connection conn,
 String schemaName,
 String triggerName,
 String tableName,
 boolean before,
 int type)
           throws SQLException

This method is called by the database engine once when initializing the trigger. It is called when the trigger is created, as well as when the database is opened. The type of operation is a bit field with the appropriate flags set. As an example, if the trigger is of type INSERT and UPDATE, then the parameter type is set to (INSERT | UPDATE).

Parameters:

conn - a connection to the database (a system connection)

schemaName - the name of the schema

triggerName - the name of the trigger used in the CREATE TRIGGER statement

tableName - the name of the table

before - whether the fire method is called before or after the operation is performed

type - the operation type: INSERT, UPDATE, DELETE, SELECT, or a combination (this parameter is a bit field)

Throws:

SQLException - on SQL exception

fire

void fire(Connection conn,
 Object[] oldRow,
 Object[] newRow)
   throws SQLException

This method is called for each triggered action. The method is called immediately when the operation occurred (before it is committed). A transaction rollback will also rollback the operations that were done within the trigger, if the operations occurred within the same database. If the trigger changes state outside the database, a rollback trigger should be used.

The row arrays contain all columns of the table, in the same order as defined in the table.

The trigger itself may change the data in the newRow array.

Parameters:

conn - a connection to the database

oldRow - the old row, or null if no old row is available (for INSERT)

newRow - the new row, or null if no new row is available (for DELETE)

Throws:

SQLException - if the operation must be undone

close

default void close()
            throws SQLException

This method is called when the database is closed. If the method throws an exception, it will be logged, but closing the database will continue.

Throws:

SQLException - on SQL exception

remove

default void remove()
             throws SQLException

This method is called when the trigger is dropped.

Throws:

SQLException - on SQL exception