Almost all commercial databases (and programming languages) offer a standard set of data types. These cover a multitude of situations, but not all.
It is usually possible to declare a field (or column) required, and to define a default value for it.
|Binary||A number in the base 2 format|
|BLOB||Binary Large Object (often an image)|
|Boolean||A True or false value
|Character||Any combination of letters, symbols, and numeric characters. For example, valid character data includes “928”, “Johnson”, and “(0*&(%B99nhjkJ”|
|Date||A calendar date like June 16, 1950. Format is defined in the application.|
|Decimal||A signed decimal number with up to 38 digits. The number of decimal places is specified, and can be up to 38.|
|Integer||A signed number with no decimal point (32-bit signed integers, can go from -2,147,483,648 to +2,147,483,647). (64 bit signed integers can be much bigger)|
|Long Variable Character||A potentially long string of unspecified length, typically used for “Comments” or “Notes”. It does not take up more space or require a length definition as a long string would.|
|String||Text of a specified length.|
|Time||24 hour time. Format is defined in the application.|