Entity Class Editor

Use this editor to add, delete, and edit your Entity Class and its Attributes.

Note

All the features mentioned in the Data Class Editor apply to this editor as well. This is simply an extension of those features specific to Entity Classes.

Features

Database Table
Name

The name of the database table of your Entity Class. If not specified, the name of your Entity Class is used. This value is used when the database table of your Entity Class gets generated.

Attributes

Database Field
Name

The name of the database table column of this Attribute. This value is used when the database table of your Entity Class gets generated. Allowed characters are the letters A-Z, the digits 0-9, and the underscore _.

Length

The length of the field in the database table. The following Attribute types can have their length defined and have the specified default values:

  • String : 255

  • BigDecimal : 19,2

  • BigInteger : 19,2

Changing the length has only an effect if the database schema is recreated.

Properties

  • ID: Defines the primary key field of an entity. Every Entity Class must have exactly one primary key.

  • Generated: Defines if the primary key should be generated automatically.

  • Not nullable: Defines whether the field value can be NULL in the database.

  • Unique: Defines whether the field value must be unique across the database table column.

  • Not updateable: Defines whether the column is omitted in SQL UPDATE statements generated by the persistence provider.

  • Not insertable: Defines whether the column is omitted in SQL INSERT statements generated by the persistence provider.

  • Version: Defines the version field of an entity. This is used as the optimistic lock value and ensures integrity when performing the merge operation. The following Attribute types can be used as version:

    • Short

    • Integer

    • Long

    • java.sql.Timestamp

Association

Defines the association to another Entity Class. For a bidirectional relationship, an inverse association with a mapped-by specification must be configured on the referenced Entity Class.

Cardinality

  • One-to-One: Defines a One-to-One (1:1) association to another Entity Class. Only allowed if the Attribute type is an Entity Class. The inverse association is another One-to-One association.

  • Many-to-One: Defines a Many-to-One (n:1) association to another Entity Class. Only allowed if the Attribute type is an Entity Class. The inverse association is a One-to-Many association.

  • One-to-Many: Defines a One-to-Many (1:n) association to another Entity Class. Only allowed if the Attribute type is a List or Set of an Entity Class. This association type always requires a mapped-by specification since it is the inverse of a Many-to-One association.

    Warning

    A One-to-Many association comes with a significant performance impact. Only use it if it is absolutely necessary.

Cascade

Defines the cascadable operations that are propagated to the associated Entity. If checked, operations performed on this Entity will be applied automatically to the associated Entity.

Mapped by

Defines the Attribute that owns the relationship in the associated Entity. This value must be defined on the inverse (non-owning) side of the association.

Remove orphans

If enabled and an Entity that is the target of a relationship is removed from the relationship (either by removal from the collection or by setting the relationship to null), the orphaned Entity will be removed. If the orphaned Entity is a detached, new, or removed Entity, the semantics do not apply.

If enabled and the remove operation is applied to the source Entity, the remove operation will be propagated as defined in the cascade section.

The remove operation is applied at the time of the flush operation. The orphans removal functionality is intended for Entities that are privately “owned” by their parent Entity.

Example:

A ‘Basket’ Entity holds a list of ‘Product’ Entities. What happens if basket.getProducts().remove(..) is called?

  • Remove orphans is enabled: The product is removed from the list of referenced products even if the Entity is reloaded or refreshed.

  • Remove orphans is disabled: The product stays in the list of referenced products if the Entity is reloaded or refreshed.

Note

Internally, the Java Persistence API is used to implement Entity Classes and their relations. For further details, please refer to the official Java Persistence API documentation.