Overview
This lecture explains input masks in Microsoft Access, detailing the codes used to enforce specific data entry formats in table fields.
What Are Input Masks?
- Input masks are codes that define the required format for data entered in a field.
- They ensure users enter data in the desired structure, preventing invalid entries.
Input Mask Codes
- Digits:
0 for compulsory digit (0-9), 9 for optional digit.
- Letters:
L for compulsory letter, ? for optional letter.
- Letter or Digit:
A for compulsory letter/digit, a for optional letter/digit.
- Any Character or Space:
& for compulsory, C for optional.
- Additional codes exist, but these are the main ones for beginners.
Input Mask Examples
- South African license plate: three letters, three digits, two letters =
LLL000LL.
- Use
> before letters to force uppercase (e.g., >LLL000LL).
- Use
< to force lowercase letters.
- Use
" around literal text or / before a character to display it literally.
Applying and Using Input Masks
- Access includes an Input Mask Wizard to help set up masks.
- When an input mask is set, only entries matching the format are accepted.
- Example: entering a license plate with an input mask only allows valid letters/numbers in designated positions.
Optional and Compulsory Entries
- Optional code (like
9 or a) allows a field to be left blank at that position.
- Example: phone number with an optional last digit:
000 000 0000;0;_ (last digit is optional).
Format Property vs Input Mask
> (uppercase) and < (lowercase) can also be used in the Format property to change case of entered text automatically.
Key Terms & Definitions
- Input Mask — A code pattern that specifies required data format for a field.
- Compulsory — Required value at a specific position (e.g.,
0, L, A, &).
- Optional — Value can be present or blank (e.g.,
9, ?, a, C).
- Wizard — Built-in helper for creating input masks in MS Access.
Action Items / Next Steps
- Practice creating and applying input masks to different fields in Access.
- Experiment with input masks for various data types (e.g., license plates, phone numbers).
- Explore use of Format property for auto-capitalization or lowercasing.