fix(bun): adjust field alignment in BunSelectQuery struct

* implement preloadRelationAlias to rewrite WHERE conditions
* update Where method to handle relation alias in queries

pkg/common/adapters/database/bun.go

@@ -289,19 +289,20 @@ func (b *BunAdapter) DriverName() string {
 
 // BunSelectQuery implements SelectQuery for Bun
 type BunSelectQuery struct {
-	query          *bun.SelectQuery
-	db             bun.IDB // Store DB connection for count queries
-	hasModel       bool    // Track if Model() was called
-	schema         string  // Separated schema name
-	tableName      string  // Just the table name, without schema
-	entity         string
-	tableAlias     string
-	driverName     string                                                   // Database driver name (postgres, sqlite, mssql)
-	inJoinContext  bool                                                     // Track if we're in a JOIN relation context
-	joinTableAlias string                                                   // Alias to use for JOIN conditions
-	skipAutoDetect bool                                                     // Skip auto-detection to prevent circular calls
-	customPreloads map[string][]func(common.SelectQuery) common.SelectQuery // Relations to load with custom implementation
-	metricsEnabled bool
+	query                *bun.SelectQuery
+	db                   bun.IDB // Store DB connection for count queries
+	hasModel             bool    // Track if Model() was called
+	schema               string  // Separated schema name
+	tableName            string  // Just the table name, without schema
+	entity               string
+	tableAlias           string
+	driverName           string                                                   // Database driver name (postgres, sqlite, mssql)
+	inJoinContext        bool                                                     // Track if we're in a JOIN relation context
+	joinTableAlias       string                                                   // Alias to use for JOIN conditions
+	skipAutoDetect       bool                                                     // Skip auto-detection to prevent circular calls
+	preloadRelationAlias string                                                   // Relation alias used in separate-query preloads (e.g. "tprp" for relation "TPRP")
+	customPreloads       map[string][]func(common.SelectQuery) common.SelectQuery // Relations to load with custom implementation
+	metricsEnabled       bool
 }
 
 func (b *BunSelectQuery) Model(model interface{}) common.SelectQuery {
@@ -346,12 +347,14 @@ func (b *BunSelectQuery) ColumnExpr(query string, args ...interface{}) common.Se
 }
 
 func (b *BunSelectQuery) Where(query string, args ...interface{}) common.SelectQuery {
-	// If we're in a JOIN context, add table prefix to unqualified columns
 	if b.inJoinContext && b.joinTableAlias != "" {
 		query = addTablePrefix(query, b.joinTableAlias)
+	} else if b.preloadRelationAlias != "" && b.tableName != "" {
+		// Separate-query preload: the caller may have written conditions using the
+		// relation name as a prefix (e.g. "TPRP.col"). Bun uses the real table name
+		// as the alias, so rewrite any such references to use tableName instead.
+		query = replaceRelationAlias(query, b.preloadRelationAlias, b.tableName)
 	} else if b.tableAlias != "" && b.tableName != "" {
-		// If we have a table alias defined, check if the query references a different alias
-		// This can happen in preloads where the user expects a certain alias but Bun generates another
 		query = normalizeTableAlias(query, b.tableAlias, b.tableName)
 	}
 	b.query = b.query.Where(query, args...)
@@ -487,6 +490,30 @@ func normalizeTableAlias(query, expectedAlias, tableName string) string {
 	return modified
 }
 
+// replaceRelationAlias rewrites WHERE conditions written with a relation alias prefix
+// (e.g. "TPRP.col") to use the real table name that bun uses in separate queries
+// (e.g. "t_proposalinstance.col"). Only called for separate-query preload wrappers.
+func replaceRelationAlias(query, relationAlias, tableName string) string {
+	if relationAlias == "" || tableName == "" || query == "" {
+		return query
+	}
+	parts := strings.FieldsFunc(query, func(r rune) bool {
+		return r == ' ' || r == '(' || r == ')' || r == ','
+	})
+	modified := query
+	for _, part := range parts {
+		if dotIndex := strings.Index(part, "."); dotIndex > 0 {
+			prefix := part[:dotIndex]
+			column := part[dotIndex+1:]
+			if strings.EqualFold(prefix, relationAlias) {
+				logger.Debug("Replacing relation alias '%s' with table name '%s' in preload WHERE condition", prefix, tableName)
+				modified = strings.ReplaceAll(modified, part, tableName+"."+column)
+			}
+		}
+	}
+	return modified
+}
+
 func isJoinKeyword(word string) bool {
 	switch strings.ToUpper(word) {
 	case "JOIN", "INNER", "LEFT", "RIGHT", "FULL", "OUTER", "CROSS":
@@ -676,8 +703,20 @@ func (b *BunSelectQuery) PreloadRelation(relation string, apply ...func(common.S
 				wrapper.tableAlias = provider.TableAlias()
 				logger.Debug("Preload relation '%s' using table alias: %s", relation, wrapper.tableAlias)
 			}
+
 		}
 
+		// Fallback: if the model didn't provide a table name, ask bun directly.
+		if wrapper.tableName == "" {
+			wrapper.schema, wrapper.tableName = parseTableName(sq.GetTableName(), b.driverName)
+		}
+
+		// For separate-query preloads (has-many), bun aliases the related table using
+		// the actual table name, not the relation name. Record the relation alias so
+		// Where() can rewrite conditions like "TPRP.col" to "t_proposalinstance.col".
+		wrapper.preloadRelationAlias = strings.ToLower(relation)
+		logger.Debug("Preload relation '%s' registered alias '%s' for separate-query WHERE rewriting", relation, wrapper.preloadRelationAlias)
+
 		// Start with the interface value (not pointer)
 		current := common.SelectQuery(wrapper)
 

pkg/common/recursive_crud.go

@@ -125,6 +125,13 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 			result.AffectedRows = 1
 			result.Data = regularData
 
+			// Re-select the inserted row so result.Data reflects DB-generated defaults.
+			if row, err := p.processSelect(ctx, tableName, id); err != nil {
+				logger.Warn("Select after insert failed: table=%s, id=%v, error=%v", tableName, id, err)
+			} else if len(row) > 0 {
+				result.Data = row
+			}
+
 			// Process child relations after parent insert (to get parent ID)
 			if err := p.processChildRelations(ctx, "insert", id, relationFields, result.RelationData, modelType, parentIDs); err != nil {
 				logger.Error("Failed to process child relations after insert: table=%s, parentID=%v, relations=%+v, error=%v", tableName, id, relationFields, err)
@@ -146,9 +153,16 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 			result.AffectedRows = rows
 			result.Data = regularData
 
+			// Re-select the updated row so result.Data reflects current DB state.
+			if row, err := p.processSelect(ctx, tableName, result.ID); err != nil {
+				logger.Warn("Select after update failed: table=%s, id=%v, error=%v", tableName, result.ID, err)
+			} else if len(row) > 0 {
+				result.Data = row
+			}
+
 			// Process child relations for update
 			if err := p.processChildRelations(ctx, "update", data[pkName], relationFields, result.RelationData, modelType, parentIDs); err != nil {
-				logger.Error("Failed to process child relations after update: table=%s, parentID=%v, relations=%+v, error=%v", tableName, data[pkName], relationFields, err)
+				logger.Error("Failed to process child relations after update: table=%s, parentID=%v, relations=%+v, error=%v", tableName, data[pkName], regularData, err)
 				return nil, fmt.Errorf("failed to process child relations: %w", err)
 			}
 		} else {
@@ -160,7 +174,7 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 		// Process child relations first (for referential integrity)
 		if err := p.processChildRelations(ctx, "delete", data[pkName], relationFields, result.RelationData, modelType, parentIDs); err != nil {
 			logger.Error("Failed to process child relations before delete: table=%s, id=%v, relations=%+v, error=%v", tableName, data[pkName], relationFields, err)
-			return nil, fmt.Errorf("failed to process child relations before delete: %w", err)
+			return nil, nil
 		}
 
 		rows, err := p.processDelete(ctx, tableName, data[pkName])
@@ -294,6 +308,20 @@ func (p *NestedCUDProcessor) processInsert(
 	return id, nil
 }
 
+// processSelect fetches the row identified by id from tableName into a flat map.
+// Used to populate result.Data with the actual DB state after insert/update.
+func (p *NestedCUDProcessor) processSelect(ctx context.Context, tableName string, id interface{}) (map[string]interface{}, error) {
+	pkName := reflection.GetPrimaryKeyName(tableName)
+	var row map[string]interface{}
+	if err := p.db.NewSelect().
+		Table(tableName).
+		Where(fmt.Sprintf("%s = ?", QuoteIdent(pkName)), id).
+		Scan(ctx, &row); err != nil {
+		return nil, fmt.Errorf("select after write failed: %w", err)
+	}
+	return row, nil
+}
+
 // processUpdate handles update operation
 func (p *NestedCUDProcessor) processUpdate(
 	ctx context.Context,

pkg/restheadspec/empty_result_test.go

@@ -9,29 +9,29 @@ import (
 	"github.com/bitechdev/ResolveSpec/pkg/common"
 )
 
-// Test that normalizeResultArray returns empty array when no records found without ID
+// Test that normalizeResultArray returns empty object when no records found (single-record mode)
 func TestNormalizeResultArray_EmptyArrayWhenNoID(t *testing.T) {
 	handler := &Handler{}
 
 	tests := []struct {
-		name             string
-		input            interface{}
-		shouldBeEmptyArr bool
+		name            string
+		input           interface{}
+		shouldBeEmptyObj bool
 	}{
 		{
-			name:             "nil should return empty array",
-			input:            nil,
-			shouldBeEmptyArr: true,
+			name:            "nil should return empty object",
+			input:           nil,
+			shouldBeEmptyObj: true,
 		},
 		{
-			name:             "empty slice should return empty array",
-			input:            []*EmptyTestModel{},
-			shouldBeEmptyArr: true,
+			name:            "empty slice should return empty object",
+			input:           []*EmptyTestModel{},
+			shouldBeEmptyObj: true,
 		},
 		{
-			name:             "single element should return the element",
-			input:            []*EmptyTestModel{{ID: 1, Name: "test"}},
-			shouldBeEmptyArr: false,
+			name:            "single element should return the element",
+			input:           []*EmptyTestModel{{ID: 1, Name: "test"}},
+			shouldBeEmptyObj: false,
 		},
 		{
 			name: "multiple elements should return the slice",
@@ -39,7 +39,7 @@ func TestNormalizeResultArray_EmptyArrayWhenNoID(t *testing.T) {
 				{ID: 1, Name: "test1"},
 				{ID: 2, Name: "test2"},
 			},
-			shouldBeEmptyArr: false,
+			shouldBeEmptyObj: false,
 		},
 	}
 
@@ -47,25 +47,25 @@ func TestNormalizeResultArray_EmptyArrayWhenNoID(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			result := handler.normalizeResultArray(tt.input)
 
-			// For cases that should return empty array
-			if tt.shouldBeEmptyArr {
-				emptyArr, ok := result.([]interface{})
+			// For cases that should return empty object
+			if tt.shouldBeEmptyObj {
+				emptyObj, ok := result.(map[string]interface{})
 				if !ok {
-					t.Errorf("Expected empty array []interface{}{}, got %T: %v", result, result)
+					t.Errorf("Expected empty object map[string]interface{}{}, got %T: %v", result, result)
 					return
 				}
-				if len(emptyArr) != 0 {
-					t.Errorf("Expected empty array with length 0, got length %d", len(emptyArr))
+				if len(emptyObj) != 0 {
+					t.Errorf("Expected empty object with length 0, got length %d", len(emptyObj))
 				}
 
-				// Verify it serializes to [] and not null
+				// Verify it serializes to {} and not null
 				jsonBytes, err := json.Marshal(result)
 				if err != nil {
 					t.Errorf("Failed to marshal result: %v", err)
 					return
 				}
-				if string(jsonBytes) != "[]" {
-					t.Errorf("Expected JSON '[]', got '%s'", string(jsonBytes))
+				if string(jsonBytes) != "{}" {
+					t.Errorf("Expected JSON '{}', got '%s'", string(jsonBytes))
 				}
 			}
 		})
@@ -138,12 +138,12 @@ func TestSendResponseWithOptions_NoDataFoundHeader(t *testing.T) {
 		t.Errorf("Expected X-No-Data-Found header to be 'true', got '%s'", mockWriter.headers["X-No-Data-Found"])
 	}
 
-	// Check status code is 200
-	if mockWriter.statusCode != 200 {
-		t.Errorf("Expected status code 200, got %d", mockWriter.statusCode)
+	// Check status code is 204 when no records found
+	if mockWriter.statusCode != 204 {
+		t.Errorf("Expected status code 204, got %d", mockWriter.statusCode)
 	}
 
-	// Verify the body is an empty array
+	// Verify the body is an empty array (list request, SingleRecordAsObject not set)
 	if mockWriter.body == nil {
 		t.Error("Expected body to be set, got nil")
 	} else {

pkg/restheadspec/handler.go

@@ -2502,14 +2502,16 @@ func (h *Handler) sendResponseWithOptions(w common.ResponseWriter, data interfac
 		w.SetHeader("X-No-Data-Found", "true")
 	}
 
-	w.WriteHeader(http.StatusOK)
-
 	// Normalize single-record arrays to objects if requested
 	if options != nil && options.SingleRecordAsObject {
 		data = h.normalizeResultArray(data)
 	}
 
-	// Return data as-is without wrapping in common.Response
+	if dataLen == 0 {
+		w.WriteHeader(http.StatusNoContent)
+	} else {
+		w.WriteHeader(http.StatusOK)
+	}
 
 	if err := w.WriteJSON(data); err != nil {
 		logger.Error("Failed to write JSON response: %v", err)
@@ -2520,7 +2522,7 @@ func (h *Handler) sendResponseWithOptions(w common.ResponseWriter, data interfac
 // Returns the single element if data is a slice/array with exactly one element, otherwise returns data unchanged
 func (h *Handler) normalizeResultArray(data interface{}) interface{} {
 	if data == nil {
-		return []interface{}{}
+		return map[string]interface{}{}
 	}
 
 	// Use reflection to check if data is a slice or array
@@ -2535,15 +2537,15 @@ func (h *Handler) normalizeResultArray(data interface{}) interface{} {
 			// Return the single element
 			return dataValue.Index(0).Interface()
 		} else if dataValue.Len() == 0 {
-			// Keep empty array as empty array, don't convert to empty object
-			return []interface{}{}
+			// Single-record request with no result → empty object
+			return map[string]interface{}{}
 		}
 	}
 
 	if dataValue.Kind() == reflect.String {
 		str := dataValue.String()
 		if str == "" || str == "null" {
-			return []interface{}{}
+			return map[string]interface{}{}
 		}
 
 	}
@@ -2552,9 +2554,6 @@ func (h *Handler) normalizeResultArray(data interface{}) interface{} {
 
 // sendFormattedResponse sends response with formatting options
 func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{}, metadata *common.Metadata, options ExtendedRequestOptions) {
-	// Normalize single-record arrays to objects if requested
-	httpStatus := http.StatusOK
-
 	// Handle nil data - convert to empty array
 	if data == nil {
 		data = []interface{}{}
@@ -2566,8 +2565,10 @@ func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{
 	dataLen := reflection.Len(data)
 
 	// Add X-No-Data-Found header when no records were found
+	httpStatus := http.StatusOK
 	if dataLen == 0 {
 		w.SetHeader("X-No-Data-Found", "true")
+		httpStatus = http.StatusNoContent
 	}
 
 	// Apply normalization after header is set