Merge branch 'dev/anushakolan/mcp/add-field-description' of https://github.com/Azure/data-api-builder into dev/anushakolan/mcp/add-field-description

Author: souvikghosh04

src/Core/Services/MetadataProviders/SqlMetadataProvider.cs

@@ -1094,22 +1094,72 @@ await PopulateResultSetDefinitionsForStoredProcedureAsync(
                 }
                 else if (entitySourceType is EntitySourceType.Table)
                 {
+                    // Resolve PKs from fields first
+                    List<string>? pkFields = entity.Fields?
+                        .Where(f => f.PrimaryKey)
+                        .Select(f => f.Name)
+                        .ToList();
+
+                    // Fallback to key-fields from config
+                    if (pkFields == null || pkFields.Count == 0)
+                    {
+                        pkFields = entity.Source.KeyFields?.ToList();
+                    }
+
+                    // If still empty, fallback to DB schema PKs
+                    if (pkFields == null || pkFields.Count == 0)
+                    {
+                        DataTable dataTable = await GetTableWithSchemaFromDataSetAsync(
+                            entityName,
+                            GetSchemaName(entityName),
+                            GetDatabaseObjectName(entityName));
+
+                        pkFields = dataTable.PrimaryKey.Select(pk => pk.ColumnName).ToList();
+                    }
+
+                    pkFields ??= new List<string>();
+
                     await PopulateSourceDefinitionAsync(
                         entityName,
                         GetSchemaName(entityName),
                         GetDatabaseObjectName(entityName),
                         GetSourceDefinition(entityName),
-                        entity.Source.KeyFields);
+                        pkFields);
                 }
                 else
                 {
+                    // Resolve PKs from fields first
+                    List<string>? pkFields = entity.Fields?
+                        .Where(f => f.PrimaryKey)
+                        .Select(f => f.Name)
+                        .ToList();
+
+                    // Fallback to key-fields from config
+                    if (pkFields == null || pkFields.Count == 0)
+                    {
+                        pkFields = entity.Source.KeyFields?.ToList();
+                    }
+
+                    // If still empty, fallback to DB schema PKs
+                    if (pkFields == null || pkFields.Count == 0)
+                    {
+                        DataTable dataTable = await GetTableWithSchemaFromDataSetAsync(
+                            entityName,
+                            GetSchemaName(entityName),
+                            GetDatabaseObjectName(entityName));
+
+                        pkFields = dataTable.PrimaryKey.Select(pk => pk.ColumnName).ToList();
+                    }
+
+                    pkFields ??= [];
+
                     ViewDefinition viewDefinition = (ViewDefinition)GetSourceDefinition(entityName);
                     await PopulateSourceDefinitionAsync(
                         entityName,
                         GetSchemaName(entityName),
                         GetDatabaseObjectName(entityName),
                         viewDefinition,
-                        entity.Source.KeyFields);
+                        pkFields);
                 }
             }
             catch (Exception e)
@@ -1264,19 +1314,9 @@ private async Task PopulateSourceDefinitionAsync(
             string schemaName,
             string tableName,
             SourceDefinition sourceDefinition,
-            string[]? runtimeConfigKeyFields)
+            List<string> pkFields)
         {
-            DataTable dataTable = await GetTableWithSchemaFromDataSetAsync(entityName, schemaName, tableName);
-
-            List<DataColumn> primaryKeys = new(dataTable.PrimaryKey);
-            if (runtimeConfigKeyFields is null || runtimeConfigKeyFields.Length == 0)
-            {
-                sourceDefinition.PrimaryKey = new(primaryKeys.Select(primaryKey => primaryKey.ColumnName));
-            }
-            else
-            {
-                sourceDefinition.PrimaryKey = new(runtimeConfigKeyFields);
-            }
+            sourceDefinition.PrimaryKey = [.. pkFields];
 
             if (sourceDefinition.PrimaryKey.Count == 0)
             {
@@ -1292,6 +1332,7 @@ private async Task PopulateSourceDefinitionAsync(
                 await PopulateTriggerMetadataForTable(entityName, schemaName, tableName, sourceDefinition);
             }
 
+            DataTable dataTable = await GetTableWithSchemaFromDataSetAsync(entityName, schemaName, tableName);
             using DataTableReader reader = new(dataTable);
             DataTable schemaTable = reader.GetSchemaTable();
             RuntimeConfig runtimeConfig = _runtimeConfigProvider.GetConfig();

src/Service.Tests/TestHelper.cs

@@ -80,7 +80,7 @@ public static RuntimeConfig AddMissingEntitiesToConfig(RuntimeConfig config, str
         {
             Entity entity = new(
                 Source: new(entityName, EntitySourceType.Table, null, keyfields),
-                Fields: null,
+                Fields: new List<FieldMetadata> { new() { Name = keyfields?[0], PrimaryKey = true } },
                 GraphQL: new(entityKey, entityKey.Pluralize()),
                 Rest: new(Enabled: true),
                 Permissions: new[]