GeneratedValue
annotation. A table generator
may be specified on the entity class or on the primary
key field or property. The scope of the generator name
is global to the persistence unit (across all generator
types).
If no name is explicitly specified, and the annotation occurs on an entity class or primary key attribute of an entity class, then the name defaults to the name of the entity.
If no name is explicitly specified, and the annotation occurs
on a package descriptor, then the annotation defines a recipe for
producing a default generator when a GeneratedValue
annotation of any program element in the annotated package has
strategy=TABLE
and a defaulted
generator name. The name of
this default generator is the defaulted generator name, and its
other properties are determined by the members of the package
TableGenerator
annotation.
Example 1:
@Entity
public class Employee {
...
@TableGenerator(
name = "empGen",
table = "ID_GEN",
pkColumnName = "GEN_KEY",
valueColumnName = "GEN_VALUE",
pkColumnValue = "EMP_ID",
allocationSize = 1)
@Id
@GeneratedValue(strategy = TABLE, generator = "empGen")
int id;
...
}
Example 2:
@Entity
public class Address {
...
@TableGenerator(
table = "ID_GEN",
pkColumnName = "GEN_KEY",
valueColumnName = "GEN_VALUE",
pkColumnValue = "ADDR_ID")
@Id
@GeneratedValue(strategy = TABLE)
int id;
...
}
- Since:
- 1.0
- See Also:
-
Optional Element Summary
Modifier and TypeOptional ElementDescriptionint
(Optional) The amount to increment by when allocating id numbers from the generator.(Optional) The catalog of the table.Index[]
(Optional) Indexes for the table.int
(Optional) The initial value to be used to initialize the column that stores the last value generated.(optional) A unique generator name that can be referenced by one or more classes to be the generator for id values.(Optional) A SQL fragment appended to the generated DDL statement which creates this table.(Optional) Name of the primary key column in the table.(Optional) The primary key value in the generator table that distinguishes this set of generated values from others that may be stored in the table.(Optional) The schema of the table.(Optional) Name of the table that stores the generated id values.(Optional) Unique constraints that are to be placed on the table.(Optional) Name of the column that stores the last value generated.
-
Element Details
-
name
String name(optional) A unique generator name that can be referenced by one or more classes to be the generator for id values.Defaults to the name of the entity when the annotation occurs on an entity class or primary key attribute.
- Default:
""
-
table
String table(Optional) Name of the table that stores the generated id values.Defaults to a name chosen by persistence provider.
- Default:
""
-
catalog
String catalog(Optional) The catalog of the table.Defaults to the default catalog.
- Default:
""
-
schema
String schema(Optional) The schema of the table.Defaults to the default schema for user.
- Default:
""
-
pkColumnName
String pkColumnName(Optional) Name of the primary key column in the table.Defaults to a provider-chosen name.
- Default:
""
-
valueColumnName
String valueColumnName(Optional) Name of the column that stores the last value generated.Defaults to a provider-chosen name.
- Default:
""
-
pkColumnValue
String pkColumnValue(Optional) The primary key value in the generator table that distinguishes this set of generated values from others that may be stored in the table.Defaults to a provider-chosen value to store in the primary key column of the generator table
- Default:
""
-
initialValue
int initialValue(Optional) The initial value to be used to initialize the column that stores the last value generated.- Default:
0
-
allocationSize
int allocationSize(Optional) The amount to increment by when allocating id numbers from the generator.- Default:
50
-
uniqueConstraints
UniqueConstraint[] uniqueConstraints(Optional) Unique constraints that are to be placed on the table. These are only used if table generation is in effect. These constraints apply in addition to primary key constraints.Defaults to no additional constraints.
- Default:
{}
-
indexes
Index[] indexes(Optional) Indexes for the table. These are only used if table generation is in effect. Note that it is not necessary to specify an index for a primary key, as the primary key index is created automatically.- Since:
- 2.1
- Default:
{}
-
options
String options(Optional) A SQL fragment appended to the generated DDL statement which creates this table.- Since:
- 3.2
- Default:
""
-