For more, see Modify DBF Structure
Located: Modify DBF Structure tool
The characteristic of fields and variables defining what types of data values they can store.
Examples of data types are:
String: Text or combinations of text and numbers with a maximum width of 255 characters.
Long: Whole number field. Rounds decimals to nearest whole number. User does not define field length.
Double: Double precision (precision to two decimal places) number field. User does not define field length.
Boolean: True or False.
Date: Date and time values. User does not define field length.