javax.persistence.Column Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Linda DeMichiel - Java Persistence 2.1
* Linda DeMichiel - Java Persistence 2.0
*
******************************************************************************/
package javax.persistence;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Specifies the mapped column for a persistent property or field.
* If no Column annotation is specified, the default values apply.
*
*
* Example 1:
*
* @Column(name="DESC", nullable=false, length=512)
* public String getDescription() { return description; }
*
* Example 2:
*
* @Column(name="DESC",
* columnDefinition="CLOB NOT NULL",
* table="EMP_DETAIL")
* @Lob
* public String getDescription() { return description; }
*
* Example 3:
*
* @Column(name="ORDER_COST", updatable=false, precision=12, scale=2)
* public BigDecimal getCost() { return cost; }
*
*
*
*
* @since Java Persistence 1.0
*/
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface Column {
/**
* (Optional) The name of the column. Defaults to
* the property or field name.
*/
String name() default "";
/**
* (Optional) Whether the column is a unique key. This is a
* shortcut for the UniqueConstraint annotation at the table
* level and is useful for when the unique key constraint
* corresponds to only a single column. This constraint applies
* in addition to any constraint entailed by primary key mapping and
* to constraints specified at the table level.
*/
boolean unique() default false;
/**
* (Optional) Whether the database column is nullable.
*/
boolean nullable() default true;
/**
* (Optional) Whether the column is included in SQL INSERT
* statements generated by the persistence provider.
*/
boolean insertable() default true;
/**
* (Optional) Whether the column is included in SQL UPDATE
* statements generated by the persistence provider.
*/
boolean updatable() default true;
/**
* (Optional) The SQL fragment that is used when
* generating the DDL for the column.
* Defaults to the generated SQL to create a
* column of the inferred type.
*/
String columnDefinition() default "";
/**
* (Optional) The name of the table that contains the column.
* If absent the column is assumed to be in the primary table.
*/
String table() default "";
/**
* (Optional) The column length. (Applies only if a
* string-valued column is used.)
*/
int length() default 255;
/**
* (Optional) The precision for a decimal (exact numeric)
* column. (Applies only if a decimal column is used.)
* Value must be set by developer if used when generating
* the DDL for the column.
*/
int precision() default 0;
/**
* (Optional) The scale for a decimal (exact numeric) column.
* (Applies only if a decimal column is used.)
*/
int scale() default 0;
}