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What are the data types of access and what are their functions?
Access database provides 10 data types for fields: text, remarks, numeric value, date/time, currency, autonumber, yes/no, OLE object, hyperlink and query wizard. In the design view of the table, each field has a design type.

1, text type

It is used to input text data or a combination of text and numbers. The maximum length is 255 characters (bytes) and the default value is 50. In Access, every Chinese character and all special characters (including Chinese punctuation marks) are counted as one character. If the string is less than 50 characters, the insufficient part of EmpName will be filled with spaces.

2. Currency type

Used to store monetary value, accounting for 8 bytes, and rounding is prohibited during calculation. This type is a special type of numeric data type, which is equivalent to a double-precision numeric field type. When you enter data in the currency field, you don't need to type RMB symbols and thousands of commas. Access will automatically display the RMB symbol and comma, and add two decimal places in the currency field.

3. Number type

Used for data that can be calculated by numbers, except currency. According to the size of the field, the number field can be divided into seven situations: byte, integer, long integer, single precision, double precision, synchronous copy ID and decimal, accounting for 1, 2, 4, 8, 16 and 12 bytes respectively. Indication: Just write directly. For example: 324629 1

4. Date/Time Type

Used to store date and/or time values, accounting for 8 bytes. Indication: Enclosed in English characters #. For example: #20 10-02-25#, 02/25/20 10#, 20 10-02-25? 15: 30 #, # 20 10-02-25 at 3: 30 pm # and # 15:30# are all legal representations. But be careful: there should be a space between the date and the time.

5. Automatic numbering type

Used to automatically insert the serial number when adding records (1 or random number every time). By default, it is a long integer, or it can be changed to the synchronous replication ID. Automatic numbering cannot be updated.

6. Yes/No Type

Used to represent logical values (yes/no, true/false), accounting for 1 byte. Representation method:. True or false. This field is set for fields that only contain two different optional values. Through the format characteristics of Yes/No data type, users can select Yes/No fields.

7. Note types

Used for long text or a combination of long text and numbers (more than 255 characters), with a maximum length of 65535 characters. This type is used to store long text and numbers, and it allows fields to store up to 64,000 characters. However, Access cannot sort or index memo fields, but it can sort and index text fields.

8.OLE object types

OLE objects (such as Word documents, Excel spreadsheets, pictures, sounds, etc. ) created by using OLE protocol in other programs, and can store at most 1GB (limited by disk space).

9. Hyperlink Type: used to store hyperlink addresses, with a maximum of 64,000 characters. A hyperlink can contain at most three parts: one is the text displayed in a field or control; The second is the path of the file or page; The third is the address in the file or page. The easiest way to insert a hyperlink address in this field or control is to click Hyperlink on the Insert menu.

10, consulting wizard type

Allows users to select values from other tables or lists of values through combo boxes or list boxes. The actual field type and length depend on the data source.

References:

Baidu Encyclopedia-Data Type