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## Adding and Editing Expressions

Create customized expressions if none of the predefined expressions meet your requirements. For details about data identifier expressions, see Expressions.

### Procedure

1. On the left navigation bar, click Data Loss Prevention → Data Identifiers.
   A list of data identifiers appears.
2. Click the Expressions tab.
3. Click Add or edit an expression by clicking the expression’s name.
   A new screen displays.
4. Type a name for the expression.
   The name must not exceed 512 bytes in length.
5. Type a description that does not exceed 2048 bytes in length.
6. Type the expression and specify whether it is case-sensitive.
7. Type the displayed data.
   For example, if you are creating an expression for ID numbers, type a sample ID number. This data is used for reference purposes only and will not appear elsewhere in the product.
8. Choose one of the following criteria and configure additional settings for the chosen criteria:
   - None
   - Specific characters
   - Suffix
   - Single-character separator
9. Select an additional validation method if necessary.
   These additional validators were specifically designed to detect highly specialized digital assets.
10. Test the expression against an actual data.
    For example, if the expression is for a national ID, type a valid ID number in the Test data text box, click Test, and then check the result.
11. Click Save if you are satisfied with the result.

    | ##### Tip Save the settings only if the testing was successful. An expression that cannot detect any data wastes system resources and may impact performance.