| SAS/ACCESS Interface to CA-IDMS Software: Reference |
Each CA-IDMS database consists of database records that
are grouped into record types. A record type consists of the
record's name, all of its elements, and the elements' attributes, such as
data types and sizes. These record types are linked together through different
logical groups called sets. Sets are defined to the schema.
A set is a logical relationship established
between two or more named record types. One record type is the owner of the
set and the other record types are members. Record types can belong to more
than one set, so a record type can be both an owner of one set and a member
of another. That same record type can also be a member of more than one set.
These sets and their interweaving relationships make up a network
and give CA-IDMS its network capabilities.
To move through the database, each record type contains
pointers to other record types in its set or sets. Pointers
identify the next record in the set and link the records together in a chain.
There are three kinds of pointers:
-
Next pointer (required pointer)
- points to the next record type in the set,
regardless of whether the record type is an owner or a member of the set.
-
Prior pointer
- works the same way as the Next pointer except
that it points to the prior record type.
-
Owner pointer
- points from a member record type to the
owner record type.
Through these pointers, a program can navigate through
the network and travel a specific path through one or many sets.
The database administrator is responsible for defining
record types and sets in the schema.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
