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EOAdaptor.Concepts
Creating an EOAdaptor Subclass
Enterprise Objects Framework provides concrete adaptors for three standard relational database management systems-Informix, Oracle, and Sybase-as well as a concrete adaptor for ODBC-compliant databases. You may want to create a subclass of one of these adaptors to extend its behavior, or you may want to create a concrete EOAdaptor subclass for a different database or persistent storage system. EOAdaptor provides many default method implementations that are sufficient for concrete subclasses:
- assignExternalInfoForEntireModel
- connectionDictionary
- contexts
- delegate
- hasOpenChannels
- name
The following methods establish structure and conventions that other Enterprise Objects Framework classes depend on and should be overridden with caution:
- adaptorWithModel
- adaptorWithName
- setExpressionClassName
- setConnectionDictionary
- setDelegate
If you override setConnectionDictionary or setDelegate, your implementations should incorporate the superclass's implementation through a message to super.
The remaining EOAdaptor methods must be overridden by concrete adaptor subclasses in terms of the persistent storage system with which it interacts:
- assignExternalInfoForAttribute
- assignExternalInfoForEntity
- externalTypesWithModel
- internalTypeForExternalType
- assertConnectionDictionaryIsValid
- createAdaptorContext
- fetchedValueForDataValue
- fetchedValueForDateValue
- fetchedValueForNumberValue
- fetchedValueForStringValue
- fetchedValueForValue
- isValidQualifierType
© 2001 Apple Computer, Inc. (Last Published April 13, 2001)