Correct table-level data classification guidance

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

@@ -11,7 +11,7 @@ application-area: [all]
 
 ## Description
 
-`DataClassification` is the AL property that 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. It is required on any field that holds personal, customer, or organization data. When the property is omitted, AL applies `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 setting it to `SystemMetadata` ("no user or customer data") to silence the requirement, are both under-classifications and privacy bugs, even though the code still compiles.
+`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
 

microsoft/knowledge/privacy/table-level-data-classification-cascades.good.al

@@ -1,18 +1,21 @@
 table 50202 "System Configuration Log"
 {
+    DataClassification = SystemMetadata;
+
     fields
     {
         field(1; "Entry No."; Integer)
         {
-            DataClassification = SystemMetadata;
         }
-        field(2; "Changed By"; Code[50])
+        field(2; "Setting Name"; Text[100])
+        {
+        }
+        field(3; "Changed At"; DateTime)
         {
-            DataClassification = EndUserIdentifiableInformation;
         }
-        field(3; "Change Description"; Text[250])
+        field(4; "Changed By"; Code[50])
         {
-            DataClassification = CustomerContent;
+            DataClassification = EndUserIdentifiableInformation;
         }
     }
 
@@ -21,3 +24,17 @@ table 50202 "System Configuration Log"
         key(PK; "Entry No.") { Clustered = true; }
     }
 }
+
+tableextension 50203 "System Config Log Correlation" extends "System Configuration Log"
+{
+    fields
+    {
+        // A table extension cannot set the table-level property and does not inherit
+        // the base table's default, so this field must classify itself even though
+        // SystemMetadata is the value the base table already declares.
+        field(50203; "Correlation Id"; Guid)
+        {
+            DataClassification = SystemMetadata;
+        }
+    }
+}

microsoft/knowledge/privacy/table-level-data-classification-cascades.md

@@ -1,24 +1,24 @@
 ---
 bc-version: [all]
 domain: privacy
-keywords: [data-classification, table-level, normal-field, appsourcecop, as0016]
+keywords: [data-classification, table-level, field-inheritance, tableextension, appsourcecop, as0016, false-positive]
 technologies: [al]
 countries: [w1]
 application-area: [all]
 ---
 
-# Set DataClassification on every Normal table field
+# Table-level DataClassification is inherited by fields
 
 ## Description
 
-AppSourceCop AS0016 requires every field whose `FieldClass` is `Normal` to declare `DataClassification` and use a value other than `ToBeClassified`. A table-level `DataClassification` property does not satisfy that field-level requirement. FlowFields and FlowFilters are handled separately by the platform and are covered by `flowfield-flowfilter-classification-systemmetadata.md`.
+A valid table-level `DataClassification` is the effective default for the Normal fields declared inside that table object when they do not declare their own value, and AppSourceCop AS0016 accepts those fields rather than reporting them as unclassified. A field-level value overrides that default only for the field on which it is set. The default does not cross object boundaries: a `tableextension` cannot set the table-level property, and the fields it adds do not inherit the base table's value, so every Normal field a table extension adds must classify itself. FlowFields and FlowFilters are handled separately by the platform and are covered by `flowfield-flowfilter-classification-systemmetadata.md`.
 
 ## Best Practice
 
-Classify each Normal field according to the data it stores, even when every field in the table has the same classification. Repeat the property explicitly so AS0016 can verify every field.
+Use a table-level classification when it accurately describes the table's fields, and add a field-level classification only where a field stores a different kind of data. Do not flag a Normal field solely because it omits an explicit property when its own table supplies a valid default; verify whether the inherited value matches the field's data instead. A `tableextension` has no default to inherit, so require an explicit `DataClassification` on every Normal field it adds.
 
 See sample: `table-level-data-classification-cascades.good.al`.
 
 ## Anti Pattern
 
-Relying on `DataClassification` at table scope and leaving Normal fields unclassified. The table property does not cascade in the way AS0016 requires, so the fields still fail AppSourceCop validation.
+Reporting every Normal field without an explicit `DataClassification` when its own table already supplies a valid default, or requiring redundant field-level declarations that repeat the table value. The mirror-image mistake is waving through an unclassified Normal field added by a `tableextension` because the base table carries a default — a table extension inherits nothing. A real issue exists when neither scope supplies a valid classification, when a field's data requires an override of the inherited value, or when a Normal field added by a `tableextension` lacks a valid explicit `DataClassification`.