Field Names
A field name should be descriptive enough to identify the purpose of the field, without being overly long to prevent excessive typing. Enter the field name by placing the pointer in the first row of the Table Design window under the Field Name column. In order to ensure a valid field name, a field name:
- Cannot exceed 64 characters,
- Cannot include periods (.), exclamation points (!), accent grave (`), or brackets ([]),
- Cannot include spaces,
- Cannot include low-order ASCII characters,
- Cannot start with a blank space.
Data Types
The data type must be consistent with the data to be stored in the field. The “text” type is the most commonly used data type, including numbers that will not be added like social security or street address numbers. Here is a partial list of Access data types:
Data Type | Description |
---|---|
Short text | Alphanumeric characters |
Long text | Alphanumeric characters |
Number | Numeric values |
Large Number | Numeric values |
Date/Time | Date and time data |
Currency | Monetary data |
AutoNumber | Automatic number increments |
Yes/No | Logical values: Yes/No, True/False, etc. |
OLE Objects | Pictures, graphs, sound, video |
Hyperlink | Line to an Internet resource |
Attachment | External files |
Calculated | Stores calculations based on other fields |
Lookup Wizard | Displays data from another table |
A low-order ASCII character refers to the characters in the ASCII table with decimal values from 0 to 31. These characters are non-printable control codes used to manage devices, format text, and control the flow of data. Examples include the null character (ASCII 0), start of header (ASCII 1), backspace (ASCII 8), and carriage return (ASCII 13). These control characters were more relevant in older computing systems and are less commonly used in modern text processing.