Set restrictions on the characters that can be entered for an attribute definition.
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or 
/ Attribute Definitions / or / Range
Home / Tools / Layers / 
/ New or Edit / Attribute Definitions / or / Range
None
| Control | Description |
|---|---|
| Allow empty values | Select the checkbox to allow empty values to be assigned to the attribute. |
| Multiline | Select the checkbox to allow multiple lines of text to be assigned to the attribute. When editing text attributes, click the  button to display the Edit Text window.
|
| Maximum Length | Type the maximum number of characters allowed for the attribute value. |
| Regular Expression | Type a Regular Expression pattern to validate characters entered for the attribute value. (Optional) |
- Regular expressions are a powerful means of validating input for attribute values.
- Regular expressions override Maximum Length and Allow empty values settings.
- If Restrict to list is selected then Regular expressions are ignored.
Typing the following for Regular Expression would restrict values to only alphanumeric characters separated by spaces, hyphens, underscores, commas, ampersands, and brackets.
[[:alnum:] \-_,&\(\)]+
