FIND: Verifying the Existence of a Value in a Data Source

How to:

Verify the Existence of a Value in a Data Source

Available Languages: MODIFY, Maintain

The FIND function determines if a data value is in a data source field being searched. The function sets a temporary field to 1 (a non-zero value for MODIFY) if the data value is found in the data source field, and to 0 if it is not. FIND does not change the searched file's current database position. A value greater than zero confirms the presence of the data value, not the number of instances in the data source field.

You can also use FIND in a VALIDATE command to determine if a transaction field value exists in another FOCUS data source. If the field value is not in that data source, the function returns a value of 0, causing the validation test to fail and the request to reject the transaction.

You can use any number of FINDs in a COMPUTE or VALIDATE command. However, more FINDs increase processing time and require more buffer space in memory.

Limit: FIND does not work on files with different DBA passwords.

The opposite of FIND is NOT FIND. The NOT FIND function sets a temporary field to 1 if the incoming value is not in the data source and to 0 if the incoming value is in the data source.

Syntax: How to Verify the Existence of a Value in a Data Source

FIND(fieldname [AS dbfield] IN file);

where:

fieldname

Is the name of the field that contains the incoming data value.

AS dbfield

Is the name of the data source field whose values are compared to the incoming field values.

For Maintain - the AS field is required and the name must be qualified.

file

Is the name of the FOCUS data source.

For Maintain - the IN file is unnecessary since the AS field name is required and must be qualified.

Note:

FIND does not use an output argument.
Do not include a space between FIND and the left parenthesis.

Example: Verifying the Existence of a Value in Another Data Source (Maintain)

In the following example, FIND determines if a data value is found in another data source.

MAINTAIN FILE MOVIES AND VIDEOTRK
FOR ALL NEXT MOVIES.MOVIECODE INTO FILMSTK
TYPE "RC SHOULD BE 1 WHERE MOVIECODE EXISTS IN BOTH FILES";
TYPE " "
COMPUTE RC/I1;
COMPUTE I/I1=1;
REPEAT FILMSTK.FOCCOUNT
  COMPUTE RC= FIND(FILMSTK(I).MOVIECODE AS VIDEOTRK.MOVIECODE)
  TYPE "FOR MOVIECODE = <<FILMSTK(I).MOVIECODE , RC = <<RC"
  COMPUTE I=I+1;
ENDREPEAT
END

The output is:

RC SHOULD BE 1 WHERE MOVIECODE EXISTS IN BOTH FILES
 FOR MOVIECODE = 001MCA, RC = 1
 .
 .
 .
 FOR MOVIECODE = 387PLA, RC = 0
 .
 .
 .
 FOR MOVIECODE = 963CBS, RC = 1
 TRANSACTIONS: COMMITS  =    1 ROLLBACKS =    0
 SEGMENTS    : INCLUDED =    0 UPDATED   =    0 DELETED   =    0

Example: Verifying the Existence of a Value in the Same Data Source (Maintain)

In the following example, FIND determines if a data value is found in the same data source.

MAINTAIN FILE CAR
COMPUTE RETAIL_COST=31500;
COMPUTE CHECK/I1;
COMPUTE CHECK= FIND (RETAIL_COST);
   IF CHECK = 1 THEN GOTO FOUND1
      ELSE GOTO NOT1;
CASE FOUND1
TYPE "THERE IS A CAR WITH A RETAIL_COST OF <<RETAIL_COST"
-* ....
ENDCASE
CASE NOT1
TYPE "THERE IS NO CAR WITH A RETAIL_COST OF <<RETAIL_COST"
-*....
ENDCASE
-*....
END

The output is:

THERE IS A CAR WITH A RETAIL_COST OF    31,500
 TRANSACTIONS: COMMITS   =    1 ROLLBACKS =    0
 SEGMENTS    : INCLUDED  =    0 UPDATED   =    0 DELETED   =    0