Influence DB Store mapping by using annotations

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If using the CDO DBStore the mapping of the EMF/CDO model to the database backend can be influenced by several Ecore annotations to the model. Just add the below EAnnotation's to the appropriate classes/features.

This feature is implemented in current CVS HEAD and will be available in the CDO 3.0 release.

Contents

Class Annotations

The following annotations are meaningful in the context of EClasses.

<eClassifiers xsi:type="ecore:EClass" ...>
    <eAnnotations source="http://www.eclipse.org/CDO/DBStore">
        ...
    </eAnnotations>
</eClassifiers>

TableName

A class annotation for naming it's table.

<eAnnotations source="http://www.eclipse.org/CDO/DBStore">
    <details key="tableName" value="MY_TABLE_NAME"/>
</eAnnotations>

TableMapping

Exclude a class from persistence.
Sometimes you may have classes in your model that are not intended to be persisted. Without the below annotation CDO would create an empty table also for those classes, but with that annotation those classes are simply ignored.

<eAnnotations source="http://www.eclipse.org/CDO/DBStore">
    <details key="tableMapping" value="NONE"/>
</eAnnotations>

Feature Annotations

The following annotations are meaningful in the context of EStructuralFeatures.

<eStructuralFeatures xsi:type="ecore:EAttribute" ...>
    <eAnnotations source="http://www.eclipse.org/CDO/DBStore">
        ...
    </eAnnotations>
</eStructuralFeatures>

ColumnName

The feature annotation for naming it's column.

<eAnnotations source="http://www.eclipse.org/CDO/DBStore">
    <details key="columnName" value="MY_COLUMN_NAME"/>
</eAnnotations>

ColumnType

The type to be used for storing the feature in the database.
This can be used for example to store a feature of type EString in a Clob column.

<eAnnotations source="http://www.eclipse.org/CDO/DBStore">
    <details key="columnType" value="CLOB"/>
</eAnnotations>

ColumnLength

The length of the data.
Can be used for example to provide the length for a VARCHAR that was mapped from an EString feature.

<eAnnotations source="http://www.eclipse.org/CDO/DBStore">
    <details key="columnLength" value="256"/>
</eAnnotations>