How Queries Are Processed

This topic summarizes how the system recognizes and interprets the different parameters specified in an INFO/ACCESS query.

After a query is entered, the system identifies the command and passes control to the INFO/ACCESS processor. The INFO/ACCESS processor identifies the parameters in a query by looking up these elements in the following order:

The file name in the Master Dictionary
All other words to determine if they are defined in the Master Dictionary as connectives, modifiers, or relational operators
The remaining unidentified words to determine if they are defined in the file dictionary as attributes or phrases
The remaining unidentified words to determine if they are defined in the Master Dictionary as synonyms or phrases

The processor treats all remaining words, or all words enclosed in double quotes or backslashes, as literal values. All words enclosed in single quotes are assumed to be item-IDs.

If a word is not found in the file dictionary or the Master Dictionary, this error message displays:

[24] THE WORD 'A' CANNOT BE IDENTIFIED

If the use of single or double quotes has been made optional for the user’s account, and a word is not found in either dictionary, one of the two following error messages displays instead of message [24]:

[401] NO ITEMS PRESENT.

[780] ITEM 'A' NOT ON FILE.

This topic discusses optional quotes that appear in a later topic.

After looking up the previous elements, the INFO/ACCESS processor generates the report by:

Applying correlatives. These convert data to an intermediate format used for further processing.
Processing selections, sorts, totals, and control breaks.
Processing conversions. These convert data to the output format used in the report.