Microsoft Jet Database Engine SQL data type

SQL data type

The Microsoft Jet Database Engine SQL data types consist of 13 basic data types, which are defined by the Microsoft Jet Database Engine and several verified valid synonyms.
The following table lists the main data types. These synonyms are recognized in Microsoft Jet Database Engine SQL reserved words.

Data Type	Storage size	Description
Binary	Each character occupies one byte	Any type of data can be stored in this type of field. Data conversion is not required (for example, conversion to text data ). The way the binary field is input determines its output mode.
Bit	1 byte	Yes and no, and fields that only contain one of these two values.
Tinyint	1 byte	Integer between 0 and 255.
Money	8 bytes	A signed integer between-922,337,203,685,477.5808 and 922,337,203,685,477.5807.
Datetime (See double)	8 bytes	The date or time value between 100 and 9999.
Uniqueidentifier	128	Unique identification number used for Remote Procedure Calls.
Real	4 bytes	Single-precision floating point number, the negative value range is from-3.402823e38 to-1.401298e-45, positive number from 1.401298e-45 to 3.402823e38, and 0.
Float	8 bytes	Double-precision floating point number. The range of negative numbers is from-1.79769313486232e308 to-4.94065645841247e-324. Positive numbers range from 4.94065645841247e-324 to 1.79769313486232e30.
Smallint	2 bytes	The number of short integers ranging from-32,768 to 32,767.
Integer	4 bytes	The number of long integers ranging from-2,147,483,648 to 2,147,483,647.
Decimal	17 bytes	The exact numeric data type that holds values from 1028-1 to-1028-1. You can define the precision (1-28) and the symbol (0-definition accuracy ). The default values are 18 and 0.
Text	Two bytes per character (See note)	The size ranges from 0 to GB.
Image	Depends on actual needs	The size ranges from 0 to GB. Used for OLE objects.
Character	Two bytes per character (See note)	The length ranges from 0 to 255 characters.

 

Note:

You can use the alter table statement to modify the base and increment values. The rows in the inserted Table have automatically generated values for columns of the New Type and increment values. If the new species and growth values match the previous species and increments, replication will occur. If this column is a primary key, an error may occur when the copy value is generated.
Characters defined as text (Memo) or char (also known as text (n) with a specific length) are stored in the Unicode representation format. Unicode characters must be stored in two bytes. For the existing Microsoft Jet Database that mainly contains character data, this may mean that the length of time for converting database files to Microsoft JET 4.0 format will be nearly doubled. However, Unicode representation of many character groups previously indicated by a single-byte character group (sbcs) can be easily compressed into a single byte. For more information, see Create Table. If the char column is defined using the compression attribute, the data is automatically compressed during data storage and extracted.