Data types in Microsoft Access
The following list summarizes all the field data types available in
Microsoft Access, their uses, and their storage sizes.
Use for text or combinations of text and numbers, such as addresses,
or for numbers that do not require calculations, such as phone numbers,
part numbers, or postal codes.
Stores up to 255 characters. The FieldSize property controls the maximum
number of characters that can be entered.
Use for lengthy text and numbers, such as notes or descriptions.
Stores up to 65,536 characters.
Use for data to be included in mathematical calculations, except calculations
involving money (use Currency type).
Stores 1, 2, 4, or 8 bytes; stores 16 bytes for Replication ID (GUID).
The FieldSize property defines the specific Number type.
Use for dates and times.
Stores 8 bytes.
Use for currency values and to prevent rounding off during calculations.
Stores 8 bytes.
Use for unique sequential (incrementing by 1) or random numbers that
are automatically inserted when a record is added.
Stores 4 bytes; stores 16 bytes for Replication ID (GUID).
Use for data that can be only one of two possible values, such as Yes/No,
True/False, On/Off. Null values are not allowed.
Stores 1 bit.
Use for OLE objects (such as Microsoft Word documents, Microsoft Excel
spreadsheets, pictures, sounds, or other binary data) that were created
in other programs using the OLE protocol.
Stores up to 1 gigabyte (limited by disk space).
Use for hyperlinks. A hyperlink can be a UNC path or a URL.
Stores up to 64,000 characters.
to change columns in an existing table
Column Data Types
Indexes and primary keys