Preventing Errors

Code all programs with careful consideration to potential runtime errors. The errors most frequently encountered involve improper handling of data. These errors are attempts to assign a value that is of an inappropriate data type, format, or size to a column or field. You can test the values thoroughly and manipulate them before making an assignment using the comprehensive set of functions in the CA Ideal Procedure Definition Language (PDL).

The following are simple examples of functions that ensure that the data assigned to a column conforms to the column attributes:

The $ROUND function assigns a numeric value with two decimal positions to the field OPEN$:

SET OPEN$ = $ROUND(value,FACTOR = .01)

The $SUBSTR function assigns a two-character fixed-length value to STATE:
```
SET STATE = $SUBSTR(value,START = 1,LENGTH = 2)
```
The $VERIFY function tests a value to ensure that the value assigned to CUSTID is an alphanumeric value containing only uppercase alphanumeric characters and all digits. In this code segment, the subprocedure BADVALUE executes when another character is encountered.
```
IF $VERIFY(value,AGAINST = (UCALPHA,NUMERIC))
    SET CUSTID = value
ELSE
    DO BADVALUE
ENDIF
```
The $DATE function formats the current date value contained in the $TODAY function to the format required for ACTDT. The function $TODAY returns the current date as mmddyy, thus the $DATE function reformats the date value.
```
SET ACTDT = $DATE('YYMMDD',DATE = $TODAY)
```

For more information about CA Ideal functions, see the Programming Reference Guide.