Data type

A DATA TYPE defines a field's characteristics (which thereby determine what can be entered into that field). Microsoft Access 7.0 has 8 field basic data types: Text, Memo, Number, Date/Time, Currency, AutoNumber, Yes/No, and OLE Object. Users can also select the Lookup Wizard and follow its instructions to create data types.

A field's data type can be changed at any time, but if the field contains data, it must conform to the new data type.

NOTE: In large tables, changing a data type may take a long time.

CAUTION 1: If Access cannot convert a particular value to the new data type, it deletes the value, setting the field to null for all records containing the value.

CAUTION 2: If a field's data type is converted to a data type with a smaller field size, Access truncates data longer than the allowable field size.