jakarta.persistence.Index Maven / Gradle / Ivy
/*
* Copyright (c) 2011, 2023 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0,
* or the Eclipse Distribution License v. 1.0 which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
*/
// Contributors:
// Linda DeMichiel - 2.1
package jakarta.persistence;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* Used in schema generation to specify creation of an index.
*
* The syntax of the {@code columnList} element is given by
* the following simple BNF:
*
* {@snippet :
* column_list ::= index_column [, index_column]*
* index_column ::= column_name [ASC | DESC]
* }
*
*
If neither {@code ASC} nor {@code DESC} is not specified,
* {@code ASC}, that is, ascending order, is assumed.
*
*
Note that it is not necessary to specify an index for a
* primary key, as the primary key has a unique constraint with
* an index created automatically.
*
* @see Table
* @see SecondaryTable
* @see CollectionTable
* @see JoinTable
* @see TableGenerator
*
* @since 2.1
*
*/
@Target({})
@Retention(RUNTIME)
public @interface Index {
/**
* (Optional) The name of the index.
*
Defaults to a provider-generated name.
*/
String name() default "";
/**
* (Required) The columns included in the index, in order,
* following the BNF rule {@code column_list} given above.
*/
String columnList();
/**
* (Optional) Whether the index is unique.
*/
boolean unique() default false;
/**
* (Optional) A SQL fragment appended to the generated DDL
* which creates this index.
*
* @since 3.2
*/
String options() default "";
}