An element is the unit of transfer used between CA Datacom/DB and applications issuing CA Datacom/DB commands. An element consists of one or more contiguous columns, or FIELD entity occurrences. An element should contain columns that an application program uses at run time. Each table has at least one and no more than 255 elements.

Keys and key segments set the sort order for data retrieval. A key is composed of columns, which can be non-contiguous and in any sequence. Each column in a key can be either ascending or descending in value. Each key can be up to 180 characters long. Define a maximum of 99 keys for a table and 999 keys for a database. Define any key as unique, if each row in the table specifies a unique value for the key.

You must define a master key and a native key for each table in a Datacom data map. The master key behaves like other keys, but you can enable or disable changes to the master key. The native key dictates the physical sequence in which the data is stored. The native key can be the same as the master key.