Before proceeding, download this sample VMD file that you can use to perform the steps in this section.

In this example you need to change the maximum length of the ST (String) composite. As mentioned in the section on Setting the Maximum Length of a Field, a string is a primitive data type, which makes it possible to set the maximum field length.

For this example, the purpose of setting the maximum length limit is to ensure that there are no extra characters entered for the Social Security Number (SSN) Number. Since other segment fields are also using String as a Data Type, you must create a new string composite. This is necessary since you only want to perform field length checks for the SSN Number, and no other field using the string composite.