org.h2.constraint

Class Constraint

java.lang.Object

org.h2.engine.DbObjectBase

org.h2.schema.SchemaObjectBase

org.h2.constraint.Constraint

All Implemented Interfaces:

Comparable<Constraint>, DbObject, SchemaObject

Direct Known Subclasses:

ConstraintCheck, ConstraintReferential, ConstraintUnique

public abstract class Constraint
extends SchemaObjectBase
implements Comparable<Constraint>

The base class for constraint checking.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CHECK The constraint type name for check constraints.
static String	PRIMARY_KEY The constraint type name for primary key constraints.
static String	REFERENTIAL The constraint type name for referential constraints.
protected Table	table The table for which this constraint is defined.
static String	UNIQUE The constraint type name for unique constraints.

Fields inherited from class org.h2.engine.DbObjectBase

comment, database, trace

Fields inherited from interface org.h2.engine.DbObject

AGGREGATE, COMMENT, CONSTANT, CONSTRAINT, FUNCTION_ALIAS, INDEX, RIGHT, ROLE, SCHEMA, SEQUENCE, SETTING, TABLE_OR_VIEW, TRIGGER, USER, USER_DATATYPE

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	checkExistingData(Session session) Check the existing data.
void	checkRename() Check if this object can be renamed.
abstract void	checkRow(Session session, Table t, Row oldRow, Row newRow) Check if this row fulfils the constraint.
int	compareTo(Constraint other)
abstract String	getConstraintType() The constraint type name
abstract String	getCreateSQLWithoutIndexes() Get the SQL statement to create this constraint.
String	getDropSQL() Build a SQL statement to drop this object.
abstract HashSet<Column>	getReferencedColumns(Table table) Get all referenced columns.
Table	getRefTable()
Table	getTable()
int	getType() Get the object type.
abstract Index	getUniqueIndex() Get the unique index used to enforce this constraint, or null if no index is used.
abstract boolean	isBefore() Check if this constraint needs to be checked before updating the data.
boolean	isEverything(ExpressionVisitor visitor) Visit all elements in the constraint.
boolean	isHidden() Check whether this is a hidden object that doesn't appear in the meta data and in the script, and is not dropped on DROP ALL OBJECTS.
abstract void	rebuild() This method is called after a related table has changed (the table was renamed, or columns have been renamed).
abstract void	setIndexOwner(Index index) This index is now the owner of the specified index.
abstract boolean	usesIndex(Index index) Check if this constraint needs the specified index.

Methods inherited from class org.h2.schema.SchemaObjectBase

getSchema, getSQL, initSchemaObjectBase

Methods inherited from class org.h2.engine.DbObjectBase

getChildren, getComment, getCreateSQL, getDatabase, getId, getModificationId, getName, initDbObjectBase, invalidate, isTemporary, removeChildrenAndResources, rename, setComment, setModified, setObjectName, setTemporary, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.h2.engine.DbObject

getChildren, getComment, getCreateSQL, getCreateSQLForCopy, getDatabase, getId, getName, isTemporary, removeChildrenAndResources, rename, setComment, setTemporary

Field Detail

CHECK

public static final String CHECK

The constraint type name for check constraints.

See Also:

Constant Field Values

REFERENTIAL

public static final String REFERENTIAL

The constraint type name for referential constraints.

See Also:

Constant Field Values

UNIQUE

public static final String UNIQUE

The constraint type name for unique constraints.

See Also:

Constant Field Values

PRIMARY_KEY

public static final String PRIMARY_KEY

The constraint type name for primary key constraints.

See Also:

Constant Field Values

table

protected Table table

The table for which this constraint is defined.

Method Detail

getConstraintType

public abstract String getConstraintType()

The constraint type name

Returns:

the name

checkRow

public abstract void checkRow(Session session,
            Table t,
            Row oldRow,
            Row newRow)

Check if this row fulfils the constraint. This method throws an exception if not.

Parameters:

session - the session

t - the table

oldRow - the old row

newRow - the new row

usesIndex

public abstract boolean usesIndex(Index index)

Check if this constraint needs the specified index.

Parameters:

index - the index

Returns:

true if the index is used

setIndexOwner

public abstract void setIndexOwner(Index index)

This index is now the owner of the specified index.

Parameters:

index - the index

getReferencedColumns

public abstract HashSet<Column> getReferencedColumns(Table table)

Get all referenced columns.

Parameters:

table - the table

Returns:

the set of referenced columns

getCreateSQLWithoutIndexes

public abstract String getCreateSQLWithoutIndexes()

Get the SQL statement to create this constraint.

Returns:

the SQL statement

isBefore

public abstract boolean isBefore()

Check if this constraint needs to be checked before updating the data.

Returns:

true if it must be checked before updating

checkExistingData

public abstract void checkExistingData(Session session)

Check the existing data. This method is called if the constraint is added after data has been inserted into the table.

Parameters:

session - the session

rebuild

public abstract void rebuild()

This method is called after a related table has changed (the table was renamed, or columns have been renamed).

getUniqueIndex

public abstract Index getUniqueIndex()

Get the unique index used to enforce this constraint, or null if no index is used.

Returns:

the index

checkRename

public void checkRename()

Description copied from class: DbObjectBase

Check if this object can be renamed. System objects may not be renamed.

Specified by:

checkRename in interface DbObject

Specified by:

checkRename in class DbObjectBase

getType

public int getType()

Description copied from interface: DbObject

Get the object type.

Specified by:

getType in interface DbObject

Returns:

the object type

getTable

public Table getTable()

getRefTable

public Table getRefTable()

getDropSQL

public String getDropSQL()

Description copied from class: DbObjectBase

Build a SQL statement to drop this object.

Specified by:

getDropSQL in interface DbObject

Specified by:

getDropSQL in class DbObjectBase

Returns:

the SQL statement

compareTo

public int compareTo(Constraint other)

Specified by:

compareTo in interface Comparable<Constraint>

isHidden

public boolean isHidden()

Description copied from interface: SchemaObject

Check whether this is a hidden object that doesn't appear in the meta data and in the script, and is not dropped on DROP ALL OBJECTS.

Specified by:

isHidden in interface SchemaObject

Overrides:

isHidden in class SchemaObjectBase

Returns:

true if it is hidden

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Visit all elements in the constraint.

Parameters:

visitor - the visitor

Returns:

true if every visited expression returned true, or if there are no expressions