Using scan model method for better relation handling. e.g bun When querying has-many or many-to-many relationships, you should use Model instead of the dest parameter in Scan

Author: Hein

.gitignore

@@ -23,4 +23,5 @@ go.work.sum
 
 # env file
 .env
-bin/
+bin/
+test.db

pkg/common/adapters/database/bun.go

@@ -238,6 +238,10 @@ func (b *BunSelectQuery) Scan(ctx context.Context, dest interface{}) error {
 	return b.query.Scan(ctx, dest)
 }
 
+func (b *BunSelectQuery) ScanModel(ctx context.Context) error {
+	return b.query.Scan(ctx)
+}
+
 func (b *BunSelectQuery) Count(ctx context.Context) (int, error) {
 	// If Model() was set, use bun's native Count() which works properly
 	if b.hasModel {

pkg/common/adapters/database/gorm.go

@@ -221,6 +221,13 @@ func (g *GormSelectQuery) Scan(ctx context.Context, dest interface{}) error {
 	return g.db.WithContext(ctx).Find(dest).Error
 }
 
+func (g *GormSelectQuery) ScanModel(ctx context.Context) error {
+	if g.db.Statement.Model == nil {
+		return fmt.Errorf("ScanModel requires Model() to be set before scanning")
+	}
+	return g.db.WithContext(ctx).Find(g.db.Statement.Model).Error
+}
+
 func (g *GormSelectQuery) Count(ctx context.Context) (int, error) {
 	var count int64
 	err := g.db.WithContext(ctx).Count(&count).Error

pkg/common/interfaces.go

@@ -39,6 +39,7 @@ type SelectQuery interface {
 
 	// Execution methods
 	Scan(ctx context.Context, dest interface{}) error
+	ScanModel(ctx context.Context) error
 	Count(ctx context.Context) (int, error)
 	Exists(ctx context.Context) (bool, error)
 }

pkg/restheadspec/handler.go

@@ -398,7 +398,7 @@ func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, id st
 	}
 
 	// Execute query - modelPtr was already created earlier
-	if err := query.Scan(ctx, modelPtr); err != nil {
+	if err := query.ScanModel(ctx); err != nil {
 		logger.Error("Error executing query: %v", err)
 		h.sendError(w, http.StatusInternalServerError, "query_error", "Error executing query", err)
 		return