EntityDAC

Model Mapping



There are four different mapping mechanisms in EntityDAC. Their principal differences are: which classes constitute the object model, and how the process of meta-model creation and its association with the object model is implemented.

Code Mapped Entities

The object model consists of a set of entities (TEntity class descendants). The meta-model is previously generated as a set of meta-data classes in a separate unit. Mapping is hard-coded in the entity classes implementation.

Benefits of this type of mapping are:

Disadvantages:

Attribute-mapped entities

Object model consists of a set of entities (TEntity class descendants), marked with special mapping attributes. A separate meta-model unit is not used. Instead, the meta-model and mapping are generated dynamically at run-time, based on mapping attributes.

Benefits:

Disadvantages:

XML-mapped entities

Object model consists of a set of entities (TEntity class descendants). A separate meta-model unit is not used. The meta-model and mapping are defined in an external XML-file (for example, an Entity Developer project file).

Benefits:

Disadvantages:

Attribute-mapped objects

The same as “Attribute-mapped entities” mapping, except that the object model does not consist of TEntity, but of TObject descendants.

Benefits:

Disadvantages:

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