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Tech Tip: Enforcing string length during data entry in 4D v11 SQL
Published On: December 18, 2009

In previous versions of 4D you could use string variables to automatically limit the length of a text string. When using Unicode mode in 4D v11 SQL, strings are automatically interpreted as text, limited only by the amount of memory used, not by the length in characters. A text variable can hold 2GB of data in Unicode mode.

In 4D v11 SQL you can limit the length of an entry string into a text variable to a certain number of characters using the entry filter property for this variable. For example, say we want to limit the length to three characters in the text variable named input_t.

In Entry Filter property for input_t, add three number signs ("#"):

Or in the Tool Box create an Entry Filter like this:

And then attach this Entry filter to the Entry Filter property:

The second approach is recommended because the filter needs to be changed only once and this will affect all objects where it is set.