Opaque data type

Unlike other data types (built in, complex, and distinct), the internal structure of the opaque data type is not known to the database server. Therefore, when you define an opaque type, you must provide the following information:
  • The internal structure of the opaque data type, which provides the format of the data

    You define the support functions of the opaque type to tell the database server how to interact with this internal structure.

  • The operations that are valid on the opaque data type

    You define operator functions, built-in functions, or end-user routines that handle the opaque type.

  • Extensions of the operator class of a secondary-access method so that its strategy and support functions handle the opaque data type
  • Cast functions to provide the data conversions to and from the opaque type

    The support functions of the opaque type also serve as cast functions.

You register an opaque data type with the CREATE OPAQUE TYPE statement. For information about this statement, refer to the HCL OneDB™ Guide to SQL: Syntax. For more information, see Create an opaque data type, and Write support functions.