Data containers and some parameters to commands and functions require a name. When you create a name in Visual FoxPro, apply the following rules:
Use only letters, underscores, and numbers.
Begin the name with a letter or underscore.
Use 1 to 128 characters, except for field names in free tables and index tags вЂ” those can be 10 characters at most.
Avoid words reserved by Visual FoxPro.
File names follow your operating system's conventions.