Data types and field properties in Access

Data type	Use
Text	Any combination of characters, numbers, or characters and numbers that cannot be used for calculations. A maximum of 255 characters, with a default length of 50 characters. For the specified size, the number of Chinese characters and English letters is the same.
Note	Extra long text, for comment or description, up to 65,535 characters
Digital	Values for calculations, 1, 2, 4, or 8 bytes
Date/Time	Represents a date and time that can be used for calculations up to 8 bytes
Currency	Data type representing currency, available for calculation, up to 15 digits to the left of the decimal point, accurate to 4 bits on the right, up to 8 bytes
Auto numbering	A numeric type that access provides unique values for each record, commonly used master code, 4 bytes
Yes/No	Boolean, 1 bytes, if/No, true/false, on/off, etc.
OLE Object	From other Windows application-based object linking and embedding, such as Excel tables, Word documents, pictures, sounds, etc., File Max 1GB
Hypertext links	Create a field that stores hyperlinks that can be linked to a local UNC or network URL field, consisting of 4 parts: display text, address, sub-address, ScreenTip, with # interval, up to 2048 characters
Lookup Wizard	Creates a field that allows you to select a field type from another table, list box, or combo box. When entering table data, you can select a value from a drop-down list

Field Properties	Role
Field size	Set the range of data in fields of text, data, and AutoNumber types to a maximum of 255 characters
Format	Control display and print data formats, option-predefined formats, or enter custom formats
Number of decimal digits	Specifies the number of decimal digits of the data, the default value is "Auto", the range is 0-15
IME Mode	Determines the IME mode to be set when the focus moves to the field
Input mask	Format for directing and standardizing user input data
Title	In various views, you can provide help information to the user through the title of the object
Default value	Specify default values for data, AutoNumber and OLE data type no this property
Validation rules	An expression in which the data entered by the user must satisfy the expression
effectivity text	The informational message to display when the input data does not conform to the validation rule
Required Fields	This property determines whether the Nulll value appears

Data types and field properties in Access