Java Reference
In-Depth Information
<property name="javax.persistence.schema-generation.scripts.create-target"
<property name="eclipselink.deploy-on-startup" value="true"/>
Programmatically, schema generation is determined by a series of annotations that are placed in entity classes.
The @Table annotation denotes an entity mapping to an underlying database table. By default, a table is generated for
each top-level entity and includes columns based upon the specified attributes for that entity. Therefore, the @Column
and @JoinColumn annotations are used for generating such columns for a table. Column ordering is not determined
based upon the ordering of @Column or @ JoinColumn annotations. If column ordering is important then a Data
Definition Language (DDL) script must be supplied for generation of the table. Other annotations and annotation
attributes, such as @Id , also play important roles in schema generation. Table 4-2 lists the different annotations that
are involved in schema generation, along with a brief description and the elements that can be populated for further
control over the generated schema.
Table 4-2. Schema Generation Annotations
Used for generating tables. By default, the table name is
generated from the entity name, and the entity name is
defaulted from the class name.
A secondary table is created to partition the mapping of
entity state across multiple tables.
A colletion table is created for mapping of an element
collection. The Column, AttributeOverride, and
AssociationOverride annotations may be used to override
CollectionTable mappings.
By default, join tables are created for the mapping of
many-to-many relationships and unidirectional one-to-
many relationships.
Table generator tables are used to store generated primary
key values.
Determines the name and configuration for a column within
a table.
( continued )
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