Revision as of 12:32, 15 December 2009

Functional Specification: Dali Support for JPA 2.0 Element Collection mapping

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bug 258490 - element collection support

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Project overview

This feature covers the element collection mapping in the JPA 2.0 spec as well as any EclipseLink extensions.

Goals:

• Add Generic 2.0 support for Element Collection
• Add EclipseLink 3.0 support for Element Collection with relevant extensions
• Provide the appropriate defaults and validation for these settings

Concepts

Present any concepts relevant to the feature.

EclipseLink Element Collection Functional Spec

Requirements / Functionality

Element Collection with Basic Type

• target-class - defaults to type of the Collection if generic, must be specified otherwise
• fetch - defaults to Lazy
• collection-table and @CollectionTable
  • name defaults to <Entity name>_<attribute name>
• column and @Column
  • name defaults to attribute name
  • table defaults to collection table name and is not editable
• temporal and @Temporal
• enumerated and @Enumerated
• lob and @Lob
• convert and @Convert (EclipseLink)

Element Collection Basic Type Details

Ordering Section

Element Collection with Embeddable Type

• target-class - defaults to type of the Collection if generic, must be specified otherwise
• fetch - defaults to Lazy
• collection-table and @CollectionTable
  • name defaults to <Entity name>_<attribute name>
• Attribute and Association override names are derived from the Embeddable type
  • Are we expected to support value dot notation here? Could the attribute override be specified as name="value.street"?

Element Collection Embeddable Type Details

Element Collection Map Basic Key and Basic Value

• target-class - defaults to type of the Map value if generic, must be specified otherwise
• map-key-class and @MapKeyClass - defaults to the type of the Map key if generic, must be specified otherwise and if MapKey is not
• map-key and @MapKey - this and MapKeyClass are mutually exclusive
• fetch - defaults to Lazy
• collection-table and @Collection Table
  • Name defaults to <Entity name>_<attribute name>
• Value column definition
  • column and @Column
  • temporal and @Temporal
  • enumerated and @Enumerated
  • lob and @Lob
  • convert and @Convert (EclipseLink)
• Key column definition
  • map-key-column and @MapKeyColumn
  • map-key-temporal and @MapKeyTemporal
  • map-key-enumerated and @MapKeyEnumerated
  • map-key-convert and @MapKeyConvert
• Validation errors:
  • MapKey and MapKeyClass are both specified

Element Collection Map with Basic Key and Basic Value Details

Element Collection Map Embeddable Key and Embeddable value

• target-class - defaults to type of the Map value if generic, must be specified otherwise
• fetch - defaults to Lazy
• collection-table and @Collection Table
  • Name defaults to <Entity name>_<attribute name>
• map-key-class and @MapKeyClass - defaults to the type of the Map key if generic, must be specified otherwise and if MapKey is not
• map-key and @MapKey - this and MapKeyClass are mutually exclusive
• Value overrides
  • In Xml attribute-override, in Java @AttributeOverride
  • In Xml association-override, in Java @AssociationOverride
• Key overrides
  • In Xml use map-key-attribute-override and map-key-association-override
  • In Java use AttributeOverride(name="key.<name>") and AttributeOverride(name="value.<name>)

Element Collection Map Embeddable Key and Basic value

• target-class - defaults to type of the Map value if generic, must be specified otherwise
• fetch - defaults to Lazy
• collection-table and @Collection Table
  • Name defaults to <Entity name>_<attribute name>
• map-key-class and @MapKeyClass - defaults to the type of the Map key if generic, must be specified otherwise and if MapKey is not
• map-key and @MapKey - this and MapKeyClass are mutually exclusive
• Value column definition
  • column and @Column
  • temporal and @Temporal
  • enumerated and @Enumerated
  • lob and @Lob
  • convert and @Convert (EclipseLink)
• Key overrides
  • In Xml use map-key-attribute-override and map-key-association-override
  • In Java use AttributeOverride(name="key.<name>") and AttributeOverride(name="value.<name>)

Screen shot is similar to others with the Map Value section having column and type and the Map Key section having overrides

Element Collection Map Basic Key and Embeddable Value

• target-class - defaults to type of the Map value if generic, must be specified otherwise
• map-key-class and @MapKeyClass - defaults to the type of the Map key if generic, must be specified otherwise and if MapKey is not
• map-key and @MapKey - this and MapKeyClass are mutually exclusive
• fetch - defaults to Lazy
• collection-table and @Collection Table
  • Name defaults to <Entity name>_<attribute name>
• Value overrides
  • In Xml attribute-override, in Java @AttributeOverride
  • In Xml association-override, in Java @AssociationOverride
• Key column definition
  • map-key-column and @MapKeyColumn
  • map-key-temporal and @MapKeyTemporal
  • map-key-enumerated and @MapKeyEnumerated
  • map-key-convert and @MapKeyConvert (EclipseLink)
• Validation errors:
  • MapKey and MapKeyClass are both specified

Screen shot is similar to others with the Map Value section having overrides and the Map Key having column and type

Element Collection Map Entity Key and Basic Value

• target-class - defaults to type of the Map value if generic, must be specified otherwise
• fetch - defaults to Lazy
• collection-table and @Collection Table
  • Name defaults to <Entity name>_<attribute name>
• map-key-class and @MapKeyClass - defaults to the type of the Map key if generic, must be specified otherwise and if MapKey is not
• map-key and @MapKey - this and MapKeyClass are mutually exclusive
• Value column definition
  • column and @Column
  • temporal and @Temporal
  • enumerated and @Enumerated
  • lob and @Lob
  • convert and @Convert (EclipseLink)
• Key column definition
  • map-key-join-column and @MapKeyJoinColumn
  • @MapKeyJoinColumns

Element Collection Map Entity Key and Embeddable Value

• target-class - defaults to type of the Map value if generic, must be specified otherwise
• fetch - defaults to Lazy
• collection-table and @Collection Table
  • Name defaults to <Entity name>_<attribute name>
• map-key-class and @MapKeyClass - defaults to the type of the Map key if generic, must be specified otherwise and if MapKey is not
• map-key and @MapKey - this and MapKeyClass are mutually exclusive
• Value overrides
  • In Xml attribute-override, in Java @AttributeOverride
  • In Xml association-override, in Java @AssociationOverride
• Key column definition
  • map-key-join-column and @MapKeyJoinColumn
  • @MapKeyJoinColumns

Screen shot is similar to others with the 'Map Value' section having overrides and the 'Map Key' section having join columns

Validation

Do these apply for EclipseLink?

• From the spec: An embeddable class (including an embeddable class within another embeddable class) that is contained

within an element collection must not contain an element collection, nor may it contain a relationship to an entity other than a many-to-one or one-to-one relationship. The embeddable class must be on the owning side of such a relationship and the relationship must be mapped by a foreign key mapping.

• Bidirectional relationships represented as java.util.Map collections support the use of the Map

datatype on one side of the relationship only.

• ElementCollection specified but Map value type is an entity
• ElementCollection specified but Collection type is an entity
• Both MapKey and MapKeyClass specified on an element collection
• Database validation
  • Column name and table
  • CollectionTable name, schema, catalog
  • MapKeyColumn name and table
  • MapKeyJoinColumn name, referencedColumnName, table
  • Attribute override name and column
  • Association override name and column

API

Issues

This section lists the open issues that are still pending that must be decided prior to fully implementing this project's requirements.

Future Considerations

During the research for this project the following items were identified as out of scope but are captured here as potential future enhancements. If agreed upon during the review process these should be logged in the bug system.