jakarta.persistence.Column Maven / Gradle / Ivy
/*
* Copyright (c) 2008, 2024 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
// Linda DeMichiel - 2.0
package jakarta.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 column mapped by the annotated persistent property
* or field.
*
* If no {@code Column} annotation is explicitly specified, the
* default values apply.
*
*
Example 1:
* {@snippet :
* @Column(name = "DESC", nullable = false, length = 512)
* public String getDescription() { return description; }
* }
*
*
Example 2:
* {@snippet :
* @Column(name = "DESC",
* columnDefinition = "CLOB NOT NULL",
* table = "EMP_DETAIL")
* @Lob
* public String getDescription() { return description; }
* }
*
*
Example 3:
* {@snippet :
* @Column(name = "ORDER_COST", updatable = false, precision = 12, scale = 2)
* public BigDecimal getCost() { return cost; }
* }
*
*
* Portable applications which make use of schema generation should
* explicitly specify the {@link #precision} and {@link #scale} of
* columns of type {@code numeric} or {@code decimal}.
*
* @since 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 {@link 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 the 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.
*
* The specified DDL must be written in the native SQL dialect
* of the target database, and is not portable across databases.
*/
String columnDefinition() default "";
/**
* (Optional) A SQL fragment appended to the generated DDL
* which declares this column. May not be used in conjunction
* with {@link #columnDefinition()}.
*
* The specified DDL must be written in the native SQL dialect
* of the target database, and is not portable across databases.
*
* @since 3.2
*/
String options() 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 to columns whose type is parameterized by length,
* for example, {@code varchar} or {@code varbinary} types.
*/
int length() default 255;
/**
* (Optional) The precision for a column of SQL type {@code decimal}
* or {@code numeric}, or of similar database-native type.
*
* Applies only to columns of exact numeric type.
*
* The default value {@code 0} indicates that a provider-determined
* precision should be inferred.
*/
int precision() default 0;
/**
* (Optional) The scale for a column of SQL type {@code decimal} or
* {@code numeric}, or of similar database-native type.
*
* Applies only to columns of exact numeric type.
*
* The default value {@code 0} indicates that a provider-determined
* scale should be inferred.
*/
int scale() default 0;
/**
* (Optional) The number of decimal digits to use for storing
* fractional seconds in a SQL {@code time} or {@code timestamp}
* column.
*
* Applies only to columns of time or timestamp type.
*
* The default value {@code -1} indicates that fractional seconds
* should not be stored in a {@code time} column, or that the
* maximum number of digits supported by the database and JDBC
* driver should be stored in a {@code timestamp} column.
*
* @since 3.2
*/
int secondPrecision() default -1;
/**
* (Optional) Check constraints to be applied to the column.
* These are only used if table generation is in effect.
*
* @since 3.2
*/
CheckConstraint[] check() default {};
/**
* (Optional) A comment to be applied to the column.
* This is only used if table generation is in effect.
*
* @since 3.2
*/
String comment() default "";
}