bcquality/microsoft/knowledge/privacy/data-classification-required-on-pii-fields.md

bc-version	domain	keywords	technologies	countries	application-area
all	privacy	data-classification pii gdpr customer-content table-field under-classified	al	w1	all

DataClassification is required on table fields containing sensitive data

Description

DataClassification tells the platform what kind of data a table field stores so that telemetry, GDPR data-subject requests, and the platform's audit surfaces can treat it correctly. A field declared inside a table object can set its own value or inherit a valid table-level value; a tableextension has no table-level value to inherit, so every Normal field it adds must set its own. When neither scope supplies a valid classification, the field remains ToBeClassified — a placeholder meaning "not yet reviewed", not a safe default. Leaving a field that actually holds PII (an email address, a customer name, an employee code) as ToBeClassified, or classifying it as SystemMetadata ("no user or customer data"), are both under-classifications and privacy bugs, even though the code still compiles.

Best Practice

Set DataClassification to the value that matches the data the field actually stores. A Customer."E-Mail"-style field is CustomerContent (data belonging to the tenant's customers); a personal identifier such as an employee number or user ID is EndUserIdentifiableInformation or EndUserPseudonymousIdentifiers depending on whether it is directly identifying. A field that identifies an organization rather than a person — a company registration or VAT registration number — is OrganizationIdentifiableInformation, and a financial account identifier such as a bank account number or IBAN is AccountData. Choose the classification at field definition time — fixing it later is a schema change.

See sample: data-classification-required-on-pii-fields.good.al.

Anti Pattern

Declaring a field that stores PII with DataClassification = SystemMetadata to silence the compiler warning. The field compiles but the platform now treats customer data as system metadata in telemetry, GDPR exports and admin reports.

See sample: data-classification-required-on-pii-fields.bad.al.