Working with Direct Mappings

There are two basic ways of storing object attributes directly in a database table:

• The information can be stored directly if the attribute type is comparable to a database type.

• If there is no database primitive type that is logically comparable to the attribute's type, it must be transformed on its way to and from the database.

OracleAS TopLink furnishes the following classes of direct mappings:

• Direct-to-field

• Type conversion

• Object type

• Transformation

• Serialized object

If the application's objects contain attributes that cannot be represented as direct-to-field, type conversion, or object-type mappings, then the application must provide transformation routines for saving the attributes.

If a direct-to-field mapping cannot be used to perform the desired conversion, try type conversion and object type mappings before attempting to define a custom transformation mapping.