Module litebridge.annotations
Package org.litebridgedb.orm.annotation

Annotation Interface Column

@Target({FIELD,METHOD}) @Retention(RUNTIME) public @interface Column
Annotation used to define mapping between a Java field or method and a database column. It provides metadata for ORM frameworks to map the annotated entity field or property to the corresponding column in the database table.

This annotation can be applied to fields or methods in an entity class.

Attributes: - `value`: Specifies the name of the column this field or method maps to in the database. - `joinOn`: Indicates the condition used when performing a join operation on another table. - `joinUsing`: Specifies whether the join should use the field's value as part of a "using" clause. - `generator`: References a custom ColumnValueGenerator implementation to dynamically compute or fetch the column value. - `generateUsingSequence`: Specifies the name of a database sequence to use for generating the column value.

Example Use Cases: - Static column mapping using the `value` attribute for straightforward entity-table mapping. - Dynamic column value generation through the `generator` attribute. - Sequence-based value generation for primary key fields using the `generateUsingSequence` attribute.

Note: - The `ColumnValueGenerator` referenced in the `generator` attribute provides a functional interface for computing the column's value at runtime using metadata information. - A blank or default value for an attribute signals that the feature is not applicable or disabled.

  • Required Element Summary

    Required Elements
    Modifier and Type
    Required Element
    Description
    String
    value
    Specifies the name of the database column that the annotated field or method maps to.

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    String
    generateUsingSequence
    Specifies the database sequence to be used for generating values for the annotated field or method.
    Class<? extends ColumnValueGenerator>
    generator
    Specifies a custom implementation of ColumnValueGenerator to dynamically generate or compute values for the database column during runtime.
    String
    joinOn
    Specifies the join condition used when performing a join operation on another table.
    boolean
    joinUsing
    Indicates whether the mapping should use the field's value as part of a "using" clause when performing a SQL join operation.

  • Element Details

    • value

      String value
      Specifies the name of the database column that the annotated field or method maps to. This value is used for static column mapping in the Litebridge ORM.
      Returns:
      The name of the column in the database table.

    • joinOn

      String joinOn
      Specifies the join condition used when performing a join operation on another table. This attribute allows for defining custom SQL conditions to establish the relationship between the current column and a column in another table.
      Returns:
      The join condition as a string. If left empty or not specified, no join condition is associated with this column.
      Default:
      ""

    • joinUsing

      boolean joinUsing
      Indicates whether the mapping should use the field's value as part of a "using" clause when performing a SQL join operation. This is typically applied in cases where the field represents a foreign key that should be included in the "USING" syntax for join conditions.
      Returns:
      true if the "using" clause should be applied; false otherwise.
      Default:
      false

    • generator

      Class<? extends ColumnValueGenerator> generator
      Specifies a custom implementation of ColumnValueGenerator to dynamically generate or compute values for the database column during runtime. This attribute allows for overriding the default behavior of static column value assignment by providing a generator class that implements the logic for value computation.
      Returns:
      A class that extends ColumnValueGenerator, which will be used to generate the column value. If not specified, the default is ColumnValueGenerator.class, indicating no custom generator is used. The class must have a no-argument constructor.
      Default:
      org.litebridgedb.db.spi.generator.ColumnValueGenerator.class

    • generateUsingSequence

      String generateUsingSequence
      Specifies the database sequence to be used for generating values for the annotated field or method. When provided, this sequence will be used to automatically populate the column value during insert operations.
      Returns:
      The name of the database sequence to use. If not specified, no sequence will be used.
      Default:
      ""