MS Access – Data Types
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Every field in a table has properties and these properties define the field”s characteristics and behavior. The most important property for a field is its data type. A field”s data type determines what kind of data it can store. MS Access supports different types of data, each with a specific purpose.
- The data type determines the kind of the values that users can store in any given field.
- Each field can store data consisting of only a single data type.
Here are some of the most common data types you will find used in a typical Microsoft Access database.
| Type of Data | Description | Size |
|---|---|---|
| Short Text | Text or combinations of text and numbers, including numbers that do not require calculating (e.g. phone numbers). | Up to 255 characters. |
| Long Text | Lengthy text or combinations of text and numbers. | Up to 63, 999 characters. |
| Number | Numeric data used in mathematical calculations. | 1, 2, 4, or 8 bytes (16 bytes if set to Replication ID). |
| Date/Time | Date and time values for the years 100 through 9999. | 8 bytes |
| Currency | Currency values and numeric data used in mathematical calculations involving data with one to four decimal places. | 8 bytes |
| AutoNumber | A unique sequential (incremented by 1) number or random number assigned by Microsoft Access whenever a new record is added to a table. | 4 bytes (16 bytes if set to Replication ID). |
| Yes/No | Yes and No values and fields that contain only one of two values (Yes/No, True/False, or On/Off). | 1 bit. |
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If you use previous versions of Access, you will notice a difference for two of those data types.
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In Access 2013, we now have two data types — short text and long text. In previous versions of Access these data types were called text and memo.
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The text field is referred to as short text and your memo field is now called long text.
Here are some of the other more specialized data types, you can choose from in Access.
| Data Types | Description | Size |
|---|---|---|
|
Attachment |
Files, such as digital photos. Multiple files can be attached per record. This data type is not available in earlier versions of Access. |
Up to about 2 GB. |
|
OLE objects |
OLE objects can store pictures, audio, video, or other BLOBs (Binary Large Objects) |
Up to about 2 GB. |
|
Hyperlink |
Text or combinations of text and numbers stored as text and used as a hyperlink address. |
Up to 8,192 (each part of a Hyperlink data type can contain up to 2048 characters). |
|
Lookup Wizard |
The Lookup Wizard entry in the Data Type column in the Design view is not actually a data type. When you choose this entry, a wizard starts to help you define either a simple or complex lookup field. A simple lookup field uses the contents of another table or a value list to validate the contents of a single value per row. A complex lookup field allows you to store multiple values of the same data type in each row. |
Dependent on the data type of the lookup field. |
|
Calculated |
You can create an expression that uses data from one or more fields. You can designate different result data types from the expression. |
You can create an expression that uses data from one or more fields. You can designate different result data types from the expression. |
These are all the different data types that you can choose from when creating fields in a Microsoft Access table.
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