IMS DB – Different SSA Types

IMSDBThree types of SSA’s we can see in IMSDB:

  • Unqualified SSA :- This only specifies the SEGMENT TYPE the program is interested in. Here you don’t indicate a particular occurrence of a segment because you don’t care which occurrence of a segment you get. The segment name is first eight characters padded by space upto the eighth position followed by a space in the ninth position instead of a left parenthesis. For example – HOSPITAL. This will retrieve the first occurrence of HOSPITAL segment.
  • Qualified SSA: – This is addition to the SEGMENT TYPE, also contains one or more qualification statements. A qualified SSA describes the segment occurrence a program wants to access. This description is called a qualification statement having 3 parts. A qualified statement is enclosed in parenthesis. The part names the field that DL/I will use for segment search. The second part names the Relational Operator of two bytes telling DL/I what kind of comparison to make during the search. The third part is a variable length field that contains the values for comparison during DL/I search. **Can code more than one qualification statement.
  • Fully Qualified SSA: – The SSA’s give complete information about each segment occurrence in the search hierarchy path.

Note**

  • In the ninthposition of SSA
    • A BLANK indicates unqualified SSA
    • A LEFT PARENTHESIS indicates qualified SSA
  • An ASTERISK indicates one or more command codes
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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.