Relational schema User interface
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6.2 Relational schema The schema DDL can be used to create a schema complying wi th relational rules or with
CODASYL rules. A schema defined according to relational r ules contains no set relation-
ships, and the primary and foreign keys are defined by the user.
If a schema was defined according to CODASYL rules, the utility routine BPSQLSIA can be
used to provide SQL programmers with a relational view of the CODASYL subschema.
The BPSQLSIA utility routine analyzes all the objects in a subschema and represents them
as objects in a relational database.
The list resulting from the conversion by BPSQLSIA contains all the information that
programmers need to work with SQL.
If a CODASYL subschema is to be processed on a completely relatio nal basis with SQL, it
must satisfy certain requirements. Restrictions and notes on DDL, SSL and subschema
DDL can be found in the relevant chapters.
A description of the BPSQLSIA utility routine, inclu ding an overview of the relevant restric-
tions and an example, is provided in another UDS/SQL manual (see the "Recovery, Infor-
mation and Reorganization" manual, BPSQLSIA).