Security at the Field Definition Level

Intermediate

Auto-enter, validation, and calculation options that enforce data integrity independent of the UI.

What you'll learn

Auto-enter calculations that set audit fields securely
Validation rules as a data integrity control
The "do not replace existing value" option for immutable fields
Why field-level definitions matter for API and ODBC access

Privilege sets control who can edit a field, but field definitions control what valid data looks like. Combining auto-enter calculations, validation rules, and "do not replace existing value" options creates a security layer that holds even when data comes in through the Data API or ODBC, bypassing the UI entirely.

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Auto-enter calculations for audit fields

Use auto-enter calculated values for CreatedBy, CreatedAt, ModifiedBy, ModifiedAt. Set them with "Do not replace existing value" unchecked for Modified* fields (recalculate on every change) and checked for Created* fields (set once, never replaced).

FileMaker Script

// CreatedBy field
// Auto-enter: Calculation = Get ( AccountName )
// Do not replace existing value: YES (set once)

// ModifiedBy field
// Auto-enter: Calculation = Get ( AccountName )
// Do not replace existing value: NO (recalculate on every edit)

Designing a Privilege Set Hierarchy Account Management Best Practices