Getting Started › DATACOM VIEWs › Overview

Overview

This section outlines support for SQL access to legacy data that does not conform to the standard relational model. Access to the following is now supported:

• The elements of an array, that is, single dimensional arrays that correspond to "simple repeating fields" in CA Datacom Datadictionary, are supported.
• "Redefines," that is, columns that redefine other columns (including arrays).

Compound fields are accessible (as CHAR) even if the underlying simple fields are also visible. To achieve this, DATACOM VIEW, a CA Datacom/DB extension to the CREATE VIEW statement (see CREATE VIEW), has been implemented. A DATACOM VIEW differs from a standard view as follows:

• The syntax starts with CREATE DATACOM VIEW instead of CREATE VIEW.
• Columns representing the "redefines" and the array elements that we support are now visible, but only to the CREATE DATACOM VIEW statement. The data is accessed through the view.

CREATE DATACOM VIEW is a very flexible, powerful construct. References to columns in a redefinition from a query or view that references the DATACOM VIEW are references to the columns of the view that are projected by the view. These view columns can inherit the column names of the database table, unless that column is an array, or be assigned new names. The user of the view can consider the view for each record type as a separate database table.