Package org.hibernate.dialect.unique

Class AlterTableUniqueIndexDelegate

java.lang.Object

org.hibernate.dialect.unique.AlterTableUniqueDelegate

org.hibernate.dialect.unique.AlterTableUniqueIndexDelegate

All Implemented Interfaces:

UniqueDelegate

public class AlterTableUniqueIndexDelegate
extends AlterTableUniqueDelegate

A UniqueDelegate which uses create unique index commands when necessary.

• DB2 does not allow unique constraints on nullable columns, but it does allow the creation of unique indexes instead, using create unique index ... exclude null keys or create unique where not null index, depending on flavor.
• SQL Server does allow unique constraints on nullable columns, but the semantics are that two null values are non-unique. So here we need to jump through hoops with the create unique nonclustered index ... where ... command.

Field Summary

Fields inherited from class org.hibernate.dialect.unique.AlterTableUniqueDelegate

dialect

Constructor Summary

Constructors

Constructor	Description
AlterTableUniqueIndexDelegate(Dialect dialect)

Method Summary

Modifier and Type	Method	Description
String	getAlterTableToAddUniqueKeyCommand(UniqueKey uniqueKey, Metadata metadata, SqlStringGenerationContext context)	Get the alter table command used to create the given unique key constraint, or return the empty string if the constraint was already included in the create table statement by UniqueDelegate.getTableCreationUniqueConstraintsFragment(org.hibernate.mapping.Table, org.hibernate.boot.model.relational.SqlStringGenerationContext).
String	getAlterTableToDropUniqueKeyCommand(UniqueKey uniqueKey, Metadata metadata, SqlStringGenerationContext context)	Get the alter table command used to drop the given unique key which was previously created by UniqueDelegate.getAlterTableToAddUniqueKeyCommand(org.hibernate.mapping.UniqueKey, org.hibernate.boot.Metadata, org.hibernate.boot.model.relational.SqlStringGenerationContext).

Methods inherited from class org.hibernate.dialect.unique.AlterTableUniqueDelegate

getColumnDefinitionUniquenessFragment, getTableCreationUniqueConstraintsFragment, uniqueConstraintSql

Methods inherited from class java.lang.Object

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

Constructor Details

AlterTableUniqueIndexDelegate

public AlterTableUniqueIndexDelegate(Dialect dialect)

Method Details

getAlterTableToAddUniqueKeyCommand

public String getAlterTableToAddUniqueKeyCommand(UniqueKey uniqueKey,
 Metadata metadata,
 SqlStringGenerationContext context)

Description copied from interface: UniqueDelegate

Get the alter table command used to create the given unique key constraint, or return the empty string if the constraint was already included in the create table statement by UniqueDelegate.getTableCreationUniqueConstraintsFragment(org.hibernate.mapping.Table, org.hibernate.boot.model.relational.SqlStringGenerationContext).

Specified by:

getAlterTableToAddUniqueKeyCommand in interface UniqueDelegate

Overrides:

getAlterTableToAddUniqueKeyCommand in class AlterTableUniqueDelegate

Parameters:

uniqueKey - The UniqueKey instance. Contains all information about the columns

metadata - Access to the bootstrap mapping information

context - A context for SQL string generation

Returns:

The alter table command

getAlterTableToDropUniqueKeyCommand

public String getAlterTableToDropUniqueKeyCommand(UniqueKey uniqueKey,
 Metadata metadata,
 SqlStringGenerationContext context)

Description copied from interface: UniqueDelegate

Get the alter table command used to drop the given unique key which was previously created by UniqueDelegate.getAlterTableToAddUniqueKeyCommand(org.hibernate.mapping.UniqueKey, org.hibernate.boot.Metadata, org.hibernate.boot.model.relational.SqlStringGenerationContext).

Specified by:

getAlterTableToDropUniqueKeyCommand in interface UniqueDelegate

Overrides:

getAlterTableToDropUniqueKeyCommand in class AlterTableUniqueDelegate

Parameters:

uniqueKey - The UniqueKey instance. Contains all information about the columns

metadata - Access to the bootstrap mapping information

context - A context for SQL string generation

Returns:

The alter table command