Access database field type description and the control relationship to SQL

Text nvarchar (n)

Remark ntext

Number (long integer) int

Digital (integer) smallint

Digital (single-precision) real

Digital (double-precision) float

Number (bytes) tinyint

Currency money

Date smalldatetime

Boolean bit

Attached: a script converted to SQL.

Alter TABLE TB alter COLUMN aa byte number [bytes]
Alter TABLE TB ALTER COLUMN AA long number [long integer]
Alter TABLE TB ALTER COLUMN AA short number [integral type]
Alter TABLE TB ALTER COLUMN AA single digit [mono precision
Alter TABLE TB ALTER COLUMN AA double digit [double precision]
Alter TABLE TB ALTER COLUMN AA Currency Currency
Alter TABLE TB ALTER COLUMN AA Char text
Alter TABLE TB alter COLUMN AA text (n) text, where n indicates the field size
Alter TABLE TB alter COLUMN AA binary binary
Alter TABLE TB alter COLUMN AA Counter Auto-numbering
Alter TABLE TB ALTER COLUMN AA Memo Memo
Alter TABLE TB ALTER COLUMN AA Date/Time

In the Design view of a table, each field has a design type, and access allows nine data types: text, notes, values, date/time, goods

, AutoNumber, yes/No, OLE object, Hyperlink, Query Wizard.

　 text: This type allows a maximum of 255 characters or numbers, access default size is 50 characters, and the system only saves the input to the field.

character, without saving the null character on the unused position in the text field. You can set the field Size property to control the maximum character length that can be entered.

　 Notes: This type is used to hold long-length text and numbers, allowing fields to store up to 64,000 characters of content. But Access does not

You can sort or index a Memo field, but you can sort and index a text field. Although you can search for text in the Memo field, it is not as

Search quickly in indexed text fields.


　 Digital: This field type can be used to store numeric data for arithmetic calculations, and the user can also set the field Size property to define a specific

Number type, any font specified as a numeric data type can be set to "byte", "integer", "Long Integer", "single-precision number",

There are five types of double precision, synchronous Replication ID, and decimal. In Access, you typically default to double precision.

Date/Time: This type is used to store a date, time, or date time together, and each date/Time field requires 8 bytes to store space.

　 Currency: This type is a special type of numeric data type and is equivalent to a numeric field type with double-precision attributes. Enter data into the currency field

, you do not have to type the RMB symbol and the comma in the thousand, Access automatically displays the RMB symbol and comma, and adds two decimal places to the Currency field.

When the number of decimal points is more than two bits, access rounds the data. Accuracy is 15 digits to the left of the decimal point and 4 digits to the right.


　 Auto Numbering: This type is special, and each time you add a new record to a table, Access automatically inserts a unique order or a random number

Specify a value in the Dynamic Number field. Once the AutoNumber is specified, it is permanently connected to the record. If you delete a table that contains an AutoNumber word

After a record of a segment, Access does not renumber the table AutoNumber field. When you add a record, access no longer uses the deleted

The numeric value of the AutoNumber field is re-assigned by the increment rule.


　 Yes/no: This field is based on a field that contains only two different optional values, and by the format attribute of the Yes/No data type, the user can select the Yes/No field.

　 OLE Object: This field refers to a field that allows a separate "link" or "Embed" OLE object. When you add data to an OLE Object field, OLE objects that you can link or embed in an Access table are objects that you create in other programs that use the OLE protocol program, such as Word documents, Excel spreadsheets, images, sounds, or other binary data. OLE Object fields can be up to 1GB, and are primarily limited by disk space.

　 Super Link: This field is primarily used to hold hyperlinks that contain text that is a hyperlink address or a combination of characters and numbers stored as text. When you click a hyperlink, the Web browser or access will reach the specified destination based on the hyperlink address. Hyperlinks can contain up to three parts: one is the text displayed in a field or control, the other is the path to the file or page, and the third is the address in the file or page. The simplest way to insert a hyperlink address in this field or control is to click the Hyperlink command on the Insert menu.

　 Lookup Wizard: This field type provides the user with a list of the contents of the field to be created, and you can select the listed content as the content of the field in the list.

Access database field type description and the control relationship to SQL