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Extending HCL OneDB™Beyond standard relational database objects, HCL OneDB™ can be extended to handle specialized data types, access methods, routines, and other objects. HCL OneDB™ includes many built-in extensions that are fully integrated in the database server. HCL OneDB™ also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for HCL OneDB™.
Creating extensionsYou can create user-defined data types, routines, access methods, and other database objects to suit your needs. You can use application programming interfaces to write user-defined routines and applications that access data in HCL OneDB™ databases.
User-Defined Routines and Data Types Developer's GuideThe HCL OneDB™ User-Defined Routines and Data Types Developer's Guide describes how to define new data types and enable user-defined routines (UDRs) to extend HCL OneDB™.
Create user-defined casts
Create a user-defined cast
Choose the cast mechanism

Choose the cast mechanism

The CREATE CAST statement can optionally specify the name of a cast function that implements the cast. The database server does not automatically perform data conversion on extended data types. You must specify a cast function if the two data types have different internal structures.

The database server can implement a cast with one of following mechanisms:

Perform a straight cast if two data types have internal structures that are the same
Call a cast function to perform the data conversion