Module jakarta.persistence
Package jakarta.persistence

Annotation Type 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: {@snippet :

    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.
      java.lang.String columnDefinition
      (Optional) The SQL fragment that is used when generating the DDL for the column.
      java.lang.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.
      java.lang.String name
      (Optional) The name of the column.
      boolean nullable
      (Optional) Whether the database column is nullable.
      java.lang.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.
      java.lang.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 Detail

      • name

        java.lang.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

        java.lang.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

        java.lang.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

        java.lang.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.

        Since:
        3.2
        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

        java.lang.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:
        ""