Basic System DMS PROC › SELECT Command › DSCL Select Criteria Boolean (AND/OR) Logic

DSCL Select Criteria Boolean (AND/OR) Logic

The Boolean logic support of the CRITERIA parameter is invoked by specifying either an AND or an OR between conditional tests. Remember that a conditional test consists of an operand, an operator, and a second operand. You can specify a maximum of 64 conditional tests on a single CRITERIA parameter when each is separated by a compound condition (note that the maximum allowed can be affected by sysparm VSCRIMAX). Therefore, a valid Boolean test would be:

SELECT CRITERIA=(TRKS,GT,300,AND,PCTUSED,LT,80,AND,CREDT,GT,TODAY-60)

As in the example previous, if all of the compound conditions are AND, all of the conditional tests specified must be true for the statement to be true. Therefore, the data set would have to be larger than 300 tracks AND be less than 80 percent used AND have a creation date within the last 60 days to meet the criteria. Conversely, if all of the compound conditions are OR, if any of the conditional tests are true, the statement is true.

If both AND OR compound conditions are specified on a single command, all AND conditions are logically separated by each OR. In other words, if all AND conditions are true and an OR condition is encountered, the statement is considered true. To better describe the tests involved, let's look at a few examples.

• Suppose you would like to select all data sets that are either larger than 300 tracks and have a percent used of less than 65, or that are less than or equal to 300 tracks but have a percent used less than 50. The required command would be:

  SELECT CRITERIA=(TRKS,GT,300,AND,PCTUSED,LT,65,
  

  OR,TRKS,LE,300,AND,PCTUSED,LT,50)
  

• Suppose you want to select all data sets that are larger than 50 tracks and meet one of the following criteria: either the data set is expired or the last modification date was not within the last 90 days. The command that would accomplish this is:

  SELECT CRITERIA=(TRKS,GT,50,AND,EXPDT,LT,TODAY,AND,
  

  EXPDT,NE,0,
  OR,
  

  TRKS,GT,50,AND,MODDT,LT,TODAY-90)
  

Remember that in DSCL, neither indentation nor line breaks are important to the command parser, but they can be used to make the meaning clearer to users.

Note: In this example, the TRKS,GT,50 test was specified on both sides of the OR condition. This is necessary because the OR condition logically separates the AND conditions. See what happens when the second TRKS,GT,50 test is removed:

SELECT CRITERIA=(TRKS,GT,50,AND,EXPDT,LT,TODAY,AND,

EXPDT,NE,0,

OR,

MODDT,LT,TODAY-90)

With this test, data sets will be selected if:

• Tracks are greater than 50 AND the expiration date is less than today's date AND the expiration date is not zero, OR if
• The data set has not been modified in the last 90 days.

Note: The second test now makes no comparisons for track size and will be selected regardless of its size if the modification date test is true.

• To select all data sets spanning more than 400 tracks:

  SELECT CRITERIA=(TRKS,GT,400)
  

• Select all data sets created since January 9, 1996:

  SELECT CRITERIA=(CREDT,GT,1/9/1996)
  

• Select all data sets that have not been modified within the last year:

  SELECT CRITERIA=(MODDT,LT,TODAY-365)
  

• Select all data sets that are greater than 300 tracks and that have not been modified in the last 60 days:

  SELECT CRITERIA=(TRKS,GT,300,AND,MODDT,LT,TODAY-60)
  

• Select all data sets that either do not have a valid last use date, or that have not been used in the last year:

  SELECT CRITERIA=(USEDT,EQ,0,OR,
  

  		USEDT,LT,TODAY-365)