OPAQUE data types

An OPAQUE type is a data type for which you must provide information to the database server.

You must provide this information:
  • A data structure for how the data values are stored on disk
  • Support functions to determine how to convert between the disk storage format and the user format for data entry and display
  • Secondary access methods that determine how the index on this data type is built, used, and manipulated
  • User functions that use the data type
  • A system catalog entry to register the OPAQUE type in the database
The internal structure of an OPAQUE type is not visible to the database server and can only be accessed through user-defined routines. Definitions for OPAQUE types are stored in the sysxtdtypes system catalog table. These SQL statements maintain the definitions of OPAQUE types in the database:
  • The CREATE OPAQUE TYPE statement registers a new OPAQUE type in the database.
  • The DROP TYPE statement removes a previously defined OPAQUE type from the database.

For more information about the above-mentioned SQL statements, see the HCL OneDB™ Guide to SQL: Syntax. For information about how to create OPAQUE types and an example of an OPAQUE type, see HCL OneDB User-Defined Routines and Data Types Developer's Guide.