Module jakarta.persistence

Package jakarta.persistence

Annotation Interface Column

@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface Column

Specifies the column mapped by the annotated persistent property or field.

If no Column annotation is explicitly 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; }

Portable applications which make use of schema generation should explicitly specify the precision() and scale() of columns of type numeric or decimal.

Since:

1.0

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
CheckConstraint[]	check	(Optional) Check constraints to be applied to the column.
String	columnDefinition	(Optional) The SQL fragment that is used when generating the DDL for the column.
String	comment	(Optional) A comment to be applied to the column.
boolean	insertable	(Optional) Whether the column is included in SQL INSERT statements generated by the persistence provider.
int	length	(Optional) The column length.
String	name	(Optional) The name of the column.
boolean	nullable	(Optional) Whether the database column is nullable.
String	options	(Optional) A SQL fragment appended to the generated DDL which declares this column.
int	precision	(Optional) The precision for a column of SQL type decimal or numeric, or of similar database-native type.
int	scale	(Optional) The scale for a column of SQL type decimal or numeric, or of similar database-native type.
int	secondPrecision	(Optional) The number of decimal digits to use for storing fractional seconds in a SQL time or timestamp column.
String	table	(Optional) The name of the table that contains the column.
boolean	unique	(Optional) Whether the column is a unique key.
boolean	updatable	(Optional) Whether the column is included in SQL UPDATE statements generated by the persistence provider.

Element Details

name

String name

(Optional) The name of the column. Defaults to the property or field name.

Default:

""

unique

boolean unique

(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 the primary key mapping and to constraints specified at the table level.

Default:

false

nullable

boolean nullable

(Optional) Whether the database column is nullable.

Default:

true

insertable

boolean insertable

(Optional) Whether the column is included in SQL INSERT statements generated by the persistence provider.

Default:

true

updatable

boolean updatable

(Optional) Whether the column is included in SQL UPDATE statements generated by the persistence provider.

Default:

true

columnDefinition

String columnDefinition

(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.

Default:

""

options

String options

(Optional) A SQL fragment appended to the generated DDL which declares this column. May not be used in conjunction with 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

Default:

""

table

String table

(Optional) The name of the table that contains the column. If absent the column is assumed to be in the primary table.

Default:

""

length

int length

(Optional) The column length.

Applies only to columns whose type is parameterized by length, for example, varchar or varbinary types.

Default:

255

precision

int precision

(Optional) The precision for a column of SQL type decimal or numeric, or of similar database-native type.

Applies only to columns of exact numeric type.

The default value 0 indicates that a provider-determined precision should be inferred.

Default:

0

scale

int scale

(Optional) The scale for a column of SQL type decimal or numeric, or of similar database-native type.

Applies only to columns of exact numeric type.

The default value 0 indicates that a provider-determined scale should be inferred.

Default:

0

secondPrecision

int secondPrecision

(Optional) The number of decimal digits to use for storing fractional seconds in a SQL time or timestamp column.

Applies only to columns of time or timestamp type.

The default value -1 indicates that fractional seconds should not be stored in a time column, or that the maximum number of digits supported by the database and JDBC driver should be stored in a timestamp column.

Default:

-1

check

CheckConstraint[] check

(Optional) Check constraints to be applied to the column. These are only used if table generation is in effect.

Since:

3.2

Default:

{}

comment

String comment

(Optional) A comment to be applied to the column. This is only used if table generation is in effect.

Since:

3.2

Default:

""