Class AlterTableUniqueDelegate

java.lang.Object

org.hibernate.dialect.unique.AlterTableUniqueDelegate

All Implemented Interfaces:

UniqueDelegate

Direct Known Subclasses:

AlterTableUniqueIndexDelegate, CreateTableUniqueDelegate

public class AlterTableUniqueDelegate
extends Object
implements UniqueDelegate

A UniqueDelegate which uses alter table commands to create and drop the unique constraint. When possible, prefer CreateTableUniqueDelegate.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Dialect	dialect

Constructor Summary

Constructors

Constructor	Description
AlterTableUniqueDelegate(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(Table, 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(UniqueKey, Metadata, SqlStringGenerationContext).
String	getColumnDefinitionUniquenessFragment(Column column, SqlStringGenerationContext context)	Get the SQL fragment used to make the given column unique as part of its column definition, usually just " unique", or return an empty string if uniqueness does not belong in the column definition.
String	getTableCreationUniqueConstraintsFragment(Table table, SqlStringGenerationContext context)	Get the SQL fragment used to specify the unique constraints on the given table as part of the create table command, with a leading comma, usually something like:
protected String	uniqueConstraintSql(UniqueKey uniqueKey)

Methods inherited from class Object

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

Field Details

dialect

protected final Dialect dialect

Constructor Details

AlterTableUniqueDelegate

public AlterTableUniqueDelegate(Dialect dialect)

Parameters:

dialect - The dialect for which we are handling unique constraints

Method Details

getColumnDefinitionUniquenessFragment

public String getColumnDefinitionUniquenessFragment(Column column,
 SqlStringGenerationContext context)

Description copied from interface: UniqueDelegate

Get the SQL fragment used to make the given column unique as part of its column definition, usually just " unique", or return an empty string if uniqueness does not belong in the column definition.

This is for handling single columns explicitly marked unique, not for dealing with unique keys.

Specified by:

getColumnDefinitionUniquenessFragment in interface UniqueDelegate

Parameters:

column - The column to which to apply the unique

context - A context for SQL string generation

Returns:

The fragment (usually "unique"), empty string indicates the uniqueness will be indicated using a different approach

getTableCreationUniqueConstraintsFragment

public String getTableCreationUniqueConstraintsFragment(Table table,
 SqlStringGenerationContext context)

Description copied from interface: UniqueDelegate

Get the SQL fragment used to specify the unique constraints on the given table as part of the create table command, with a leading comma, usually something like:

, unique(x,y), constraint abc unique(a,b,c)

or return an empty string if there are no unique constraints or if the unique constraints do not belong in the table definition.

The implementation should iterate over the unique keys of the given table by calling Table.getUniqueKeys() and generate a fragment which includes all the unique key declarations.

Specified by:

getTableCreationUniqueConstraintsFragment in interface UniqueDelegate

Parameters:

table - The table for which to generate the unique constraints fragment

context - A context for SQL string generation

Returns:

The fragment, typically in the form ", unique(col1, col2), unique(col20)". The leading comma is important!

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(Table, SqlStringGenerationContext).

Specified by:

getAlterTableToAddUniqueKeyCommand in interface UniqueDelegate

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

uniqueConstraintSql

protected String uniqueConstraintSql(UniqueKey uniqueKey)

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(UniqueKey, Metadata, SqlStringGenerationContext).

Specified by:

getAlterTableToDropUniqueKeyCommand in interface UniqueDelegate

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