Ms Access 简明教程

MS Access - Data Types

表格中的每个字段都有属性，这些属性定义了字段的特征和行为。字段最重要的属性是它的数据类型。字段的数据类型决定了它可以存储哪种类型的数据。MS Access 支持不同类型的数据，每种类型都有特定用途。

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.

以下是你将在典型的 Microsoft Access 数据库中发现使用的一些最常见的数据类型。

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.

If you use previous versions of Access, you will notice a difference for two of those data types.
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.
The text field is referred to as short text and your memo field is now called long text.

以下是 Access 中一些其他更专门的数据类型，您可以从其中进行选择。

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.

这是在 Microsoft Access 表中创建字段时可以选择的所有不同数据类型。

These are all the different data types that you can choose from when creating fields in a Microsoft Access table.