when using the AND operator to evaluate two conditions, does CR do the short circuit evaluation? aka if the first expression is false, the second condition won't be evaluated. if that's the case we could write expression like

 

if not isnull(somestringfield) and somestringfield <> "" then

 

instead of using two if statements.

 

Thanks

 

Kevin

I believe it stops evaluating as soon as it hits something that makes it false. So in general you want to use more simple/efficient condition first.

however, null data and how you have it configured to handle nulls will partially imapcts the behavior.

 

If you do not explicitly write in the null handler as the first condition or use the formual editor option to 'use default values for nulls' then the crystal will stop evaluting the fomrula as soon as it hits a null.

 

(this example assumes you tha you are not using default values for nulls)

 

 

will not evaluate the same

 

 

the first statement will return "True" for nulls or empty strings and "False" for all other instances.

The second statement will return "True" for empty strings, false for non empty strings and nothing for nulls.

 

the second statement is evaluating fielda for an empty sting first, since we did not tell it how to handle the a null, it just stops evaluating and never gets to the second condition and does not return any value at all.

 

You can place these two formula fields side by side on your report to see how they act differently.

 

If you use the formula editor option setting 'Default values for null' it tells the formual how to handle the null and allows it to continue to check all of the conditions in the formula.

to make sure the string is not null first then check if the string is empty.