Digital data types use standard variable-length internal formats to store numbers.
Microsoft Jet? Database engine? SQL data type consists of 13 basic data types, which are defined by Microsoft Jet database engine and several verified synonyms. Common ones are: plastic, single precision, double precision, variable-length characters, fixed-length characters, long type, date and so on.
Extended data:
You can use Transact-SQL statements to create user-defined data types. The system stored procedure sp_addtype can be used to create user-defined data types. Its grammatical form is as follows:
sp_addtype {type}，[，system_data_bype][，' null_type']
Where type is the name of the user-defined data type. System_data_type is the data type provided by the system, such as Decimal, Int, Char, etc.
Null_type indicates how the data type handles Null values and must be enclosed in single quotation marks, such as "NULL", "NOT null" or "null".