NDB Concepts › What Is an NDB?

What Is an NDB?

NDBs let NCL programmers define, create, update, and search a database based on a collection of user-defined fields. NDBs support information storage and retrieval through the CA NetMaster and SOLVE functions. Your product provides this enhanced database manipulation facility for NCL procedures.

For example, a SHOW NDB=ALL command typically shows up to five NDBs, depending on the product.

This facility allows data to be stored, to be retrieved or updated later, in a formatted database known as a NDB. The NDB format is more powerful than standard VSAM data sets.

Note: In this guide, the term database manager refers to the assembler code that controls NDBs. There is a database manager for each active NDB.

An NDB is a formatted VSAM key-sequenced data set (KSDS). It should be accessed only by using the &NDB verbs. An NDB supports the following:

• Multiple keys, without any VSAM alternate indices
• Logical record size not limited by the defined VSAM record size
• Data access by named field, not relative field position in a record (as in a UDB)
• Transaction integrity, guaranteeing a non-corruptible file
• Multiple users, without VSAM string limitations
• Different data types, including character, numeric, floating point, hexadecimal, and date format data. The Database Manager prevents data that is not in the defined format and invalid data, from being stored (for example, the value ABC could not be stored in a field defined as numeric).
• An extremely powerful search capability, that makes full use of keys wherever possible, but does not require any keying of the search arguments.
• Null field support, which allows multiple record types to co-exist in a single NDB.
• Forward recovery facilities, minimizing the risk of data loss.