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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.
DataBlade® Developers KitThe DataBlade® Developers Kit (DBDK) guides contain information about the tools you can use to develop and package DataBlade® modules, which extend the functionality of HCL OneDB™ databases.
DataBlade® Developers Kit User's GuideThe HCL OneDB™ DataBlade® Developers Kit Users Guide describes how to use OneDB® DataBlade® Developers Kit (DBDK) tools to develop and package DataBlade® modules.
Create DataBlade® objects by using BladeSmithUse BladeSmith to create DataBlade® modules.
Create DataBlade® module objectsBladeSmith uses wizards to create and edit objects.
Create data typesYou can create extended data types in BladeSmith. In addition, you must define qualified built-in data types before you can use them in a BladeSmith project.
Opaque data typeAn opaque data type is a C structure or C++/ActiveX class. The database server does not interpret the contents of the structure. Instead, it calls support routines that you provide to manipulate the structure.
Support routinesYou can select from different categories of support routines to support your opaque data type.
Type insert and delete notification (not available for C++)The Assign() function and the Destroy() procedure perform tasks before storing or deleting an opaque data type on disk: for example, to ensure proper reference counting on smart large objects.

Type insert and delete notification (not available for C++)

The Assign() function and the Destroy() procedure perform tasks before storing or deleting an opaque data type on disk: for example, to ensure proper reference counting on smart large objects.

This category is valid for the C language.

You can provide Assign() and Destroy() routines for an opaque data type that requires special processing when an instance is stored in a database or removed from the database. The database server calls the Assign() function before it writes a value to a table. The database server calls the Destroy() procedure before it deletes a value from a table.

For example, opaque data types that include large objects require special handling before they are stored on disk or removed from a table. The database server maintains a reference count for large objects to ensure that an object is not dropped while a row in the database references it. When a reference to a large object is inserted into a table, the Assign() function increments the reference count. When a reference to a large object is deleted from a table, the Destroy() procedure decrements the reference count.

For the C language, BladeSmith prefixes the names of these functions with the name of the data type for which they are specified: OpaqueAssign() and OpaqueDestroy().