Bug fix in SQL data masking when updating rule

Author: yoavrubin

src/ResourceManager/Sql/Commands.Sql.Test/SessionRecords/Microsoft.Azure.Commands.Sql.Test.ScenarioTests.DataMaskingTests/TestDatabaseDataMaskingBasicRuleLifecycle.json

@@ -127,9 +127,21 @@ protected string ValidateRuleTarget(IEnumerable<DatabaseDataMaskingRuleModel> ru
         /// <returns>An updated rule model</returns>
         protected DatabaseDataMaskingRuleModel UpdateRule(DatabaseDataMaskingRuleModel rule)
         {
-            rule.SchemaName = SchemaName;
-            rule.TableName = TableName;
-            rule.ColumnName = ColumnName;
+            if (!string.IsNullOrEmpty(SchemaName)) // only update if the user provided this value
+            {
+                rule.SchemaName = SchemaName;
+            }
+
+            if (!string.IsNullOrEmpty(TableName)) // only update if the user provided this value
+            {
+                rule.TableName = TableName;
+            }
+
+            if (!string.IsNullOrEmpty(ColumnName)) // only update if the user provided this value
+            {
+                rule.ColumnName = ColumnName;
+            }
+
             if(!string.IsNullOrEmpty(MaskingFunction)) // only update if the user provided this value
             {
                 rule.MaskingFunction = ModelizeMaskingFunction();