fix(nestedCUD): re-select rows after insert/update for accurate state

* Ensure result.Data reflects DB-generated defaults after insert.
* Update result.Data with current DB state after update.

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 {
@@ -234,10 +248,12 @@ func (p *NestedCUDProcessor) injectForeignKeys(data map[string]interface{}, mode
 		return
 	}
 
-	for parentKey, parentID := range parentIDs {
-		dbColName := reflection.GetForeignKeyColumn(modelType, parentKey)
+	pkCol := reflection.GetPrimaryKeyName(reflect.New(modelType).Interface())
 
-		if dbColName == "" {
+	for parentKey, parentID := range parentIDs {
+		dbColNames := reflection.GetForeignKeyColumn(modelType, parentKey)
+
+		if len(dbColNames) == 0 {
 			// No explicit tag found — fall back to naming convention by scanning scalar fields.
 			for i := 0; i < modelType.NumField(); i++ {
 				field := modelType.Field(i)
@@ -248,13 +264,16 @@ func (p *NestedCUDProcessor) injectForeignKeys(data map[string]interface{}, mode
 					strings.EqualFold(jsonName, parentKey+"_id") ||
 					strings.EqualFold(jsonName, parentKey+"id") ||
 					strings.EqualFold(field.Name, parentKey+"ID") {
-					dbColName = reflection.GetColumnName(field)
+					dbColNames = []string{reflection.GetColumnName(field)}
 					break
 				}
 			}
 		}
 
-		if dbColName != "" {
+		for _, dbColName := range dbColNames {
+			if pkCol != "" && strings.EqualFold(dbColName, pkCol) {
+				continue
+			}
 			if _, exists := data[dbColName]; !exists {
 				logger.Debug("Injecting foreign key: %s = %v", dbColName, parentID)
 				data[dbColName] = parentID
@@ -289,6 +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/reflection/model_utils.go

@@ -973,23 +973,31 @@ func GetRelationType(model interface{}, fieldName string) RelationType {
 	return RelationUnknown
 }
 
-// GetForeignKeyColumn returns the DB column name of the foreign key that the
-// relation field identified by parentKey owns on modelType.
+// GetForeignKeyColumn returns the DB column names of the foreign key(s) that
+// relate parentKey to modelType. Composite keys (e.g. bun "join:a=b,join:c=d"
+// or GORM "foreignKey:ColA,ColB") yield multiple entries. Returns nil when no
+// tag is found (caller should fall back to convention).
 //
-// It checks tags in priority order:
-//  1. Bun join: tag — e.g. `bun:"rel:belongs-to,join:department_id=id"` → "department_id"
-//  2. GORM foreignKey: tag — e.g. `gorm:"foreignKey:DepartmentID"` → column of DepartmentID field
-//  3. Returns "" when no tag is found (caller should fall back to convention)
+// Two lookup strategies are tried in order:
 //
-// parentKey is matched case-insensitively against the field name and JSON tag.
-func GetForeignKeyColumn(modelType reflect.Type, parentKey string) string {
+//  1. Relation-field match: find a field whose name/json equals parentKey, then
+//     read its bun join: or GORM foreignKey: tag and return the local columns.
+//     e.g. parentKey="department", field `Department bun:"join:dept_id=id"` → ["dept_id"]
+//
+//  2. Join left-side scan: scan every bun join tag in the struct for pairs whose
+//     left side equals parentKey and return the right-side (child FK) columns.
+//     e.g. parentKey="rid_mastertaskitem", field `Children bun:"join:rid_mastertaskitem=rid_parentmastertaskitem"` → ["rid_parentmastertaskitem"]
+//     Strategy 1 is skipped if the matched field is a declared relation (rel:) or
+//     has a GORM tag but carries no explicit FK — callers should use convention.
+func GetForeignKeyColumn(modelType reflect.Type, parentKey string) []string {
 	for modelType.Kind() == reflect.Ptr || modelType.Kind() == reflect.Slice {
 		modelType = modelType.Elem()
 	}
 	if modelType.Kind() != reflect.Struct {
-		return ""
+		return nil
 	}
 
+	// Strategy 1: match parentKey against a field's name/json tag.
 	for i := 0; i < modelType.NumField(); i++ {
 		field := modelType.Field(i)
 
@@ -999,34 +1007,72 @@ func GetForeignKeyColumn(modelType reflect.Type, parentKey string) string {
 			continue
 		}
 
-		// Bun: join:local_col=foreign_col
-		for _, part := range strings.Split(field.Tag.Get("bun"), ",") {
+		bunTag := field.Tag.Get("bun")
+
+		// Bun: join:local_col=foreign_col (one join: part per pair)
+		var bunCols []string
+		for _, part := range strings.Split(bunTag, ",") {
 			part = strings.TrimSpace(part)
 			if strings.HasPrefix(part, "join:") {
-				// join: may contain multiple pairs separated by spaces: "join:a=b join:c=d"
-				// but typically it's a single pair; take the first local column
 				pair := strings.TrimPrefix(part, "join:")
 				if idx := strings.Index(pair, "="); idx > 0 {
-					return pair[:idx]
+					bunCols = append(bunCols, pair[:idx])
 				}
 			}
 		}
+		if len(bunCols) > 0 {
+			return bunCols
+		}
 
-		// GORM: foreignKey:FieldName
+		// GORM: foreignKey:FieldA,FieldB
 		for _, part := range strings.Split(field.Tag.Get("gorm"), ";") {
 			part = strings.TrimSpace(part)
 			if strings.HasPrefix(part, "foreignKey:") {
-				fkFieldName := strings.TrimPrefix(part, "foreignKey:")
-				if fkField, ok := modelType.FieldByName(fkFieldName); ok {
-					return getColumnNameFromField(fkField)
+				var cols []string
+				for _, fkFieldName := range strings.Split(strings.TrimPrefix(part, "foreignKey:"), ",") {
+					fkFieldName = strings.TrimSpace(fkFieldName)
+					if fkField, ok := modelType.FieldByName(fkFieldName); ok {
+						cols = append(cols, getColumnNameFromField(fkField))
+					}
+				}
+				if len(cols) > 0 {
+					return cols
 				}
 			}
 		}
 
-		return ""
+		// The field matched by name/json but has no explicit FK tag. If it is a
+		// declared relation field (rel:) or carries a GORM tag, the caller should
+		// use naming convention — don't fall through to strategy 2. Otherwise the
+		// matched field is a plain scalar column; proceed to the join left-side scan.
+		if strings.Contains(bunTag, "rel:") || field.Tag.Get("gorm") != "" {
+			return nil
+		}
+		break
 	}
 
-	return ""
+	// Strategy 2: scan every field's bun join tag for pairs whose left side (the
+	// parent's column) matches parentKey; the right side is the child FK column.
+	// This handles cases where parentKey is a raw column name rather than a
+	// relation field name (e.g. self-referential or has-many relationships).
+	seen := map[string]bool{}
+	var cols []string
+	for i := 0; i < modelType.NumField(); i++ {
+		for _, part := range strings.Split(modelType.Field(i).Tag.Get("bun"), ",") {
+			part = strings.TrimSpace(part)
+			if strings.HasPrefix(part, "join:") {
+				pair := strings.TrimPrefix(part, "join:")
+				if idx := strings.Index(pair, "="); idx > 0 {
+					left, right := pair[:idx], pair[idx+1:]
+					if strings.EqualFold(left, parentKey) && !seen[right] {
+						seen[right] = true
+						cols = append(cols, right)
+					}
+				}
+			}
+		}
+	}
+	return cols // nil if empty
 }
 
 // GetRelationModel gets the model type for a relation field

pkg/reflection/model_utils_foreign_key_test.go

@@ -15,6 +15,13 @@ type bunEmployee struct {
 	Department *fkDept  `bun:"rel:belongs-to,join:dept_id=id"   json:"department"`
 }
 
+// bunCompositeEmployee has a composite bun join: (two join: parts).
+type bunCompositeEmployee struct {
+	DeptID   string  `bun:"dept_id"   json:"dept_id"`
+	TenantID string  `bun:"tenant_id" json:"tenant_id"`
+	Department *fkDept `bun:"rel:belongs-to,join:dept_id=id,join:tenant_id=id" json:"department"`
+}
+
 // gormEmployee uses gorm foreignKey: tag (mirrors testmodels.Employee).
 type gormEmployee struct {
 	DepartmentID string  `json:"department_id"`
@@ -23,6 +30,24 @@ type gormEmployee struct {
 	Manager      *fkDept `gorm:"foreignKey:ManagerID;references:ID"    json:"manager"`
 }
 
+// gormCompositeEmployee has a composite GORM foreignKey.
+type gormCompositeEmployee struct {
+	DeptID   string  `json:"dept_id"`
+	TenantID string  `json:"tenant_id"`
+	Department *fkDept `gorm:"foreignKey:DeptID,TenantID" json:"department"`
+}
+
+// selfRefItem mimics a self-referential model (like mastertaskitem) where the
+// parent PK column appears as the left side of a has-many join tag.
+type selfRefItem struct {
+	RidItem       int32        `json:"rid_item" bun:"rid_item,type:integer,pk"`
+	RidParentItem int32        `json:"rid_parentitem" bun:"rid_parentitem,type:integer"`
+	// has-one (single parent pointer)
+	Parent   *selfRefItem   `json:"Parent,omitempty" bun:"rel:has-one,join:rid_item=rid_parentitem"`
+	// has-many (child collection) — same join, duplicate right-side must be deduped
+	Children []*selfRefItem `json:"Children,omitempty" bun:"rel:has-many,join:rid_item=rid_parentitem"`
+}
+
 // conventionEmployee has no explicit FK tag — relies on naming convention.
 type conventionEmployee struct {
 	DepartmentID string  `json:"department_id"`
@@ -39,20 +64,26 @@ func TestGetForeignKeyColumn(t *testing.T) {
 		name      string
 		modelType reflect.Type
 		parentKey string
-		want      string
+		want      []string
 	}{
 		// Bun join: tag
 		{
 			name:      "bun join tag returns local column",
 			modelType: reflect.TypeOf(bunEmployee{}),
 			parentKey: "department",
-			want:      "dept_id",
+			want:      []string{"dept_id"},
 		},
 		{
 			name:      "bun join tag matched via json tag (case-insensitive)",
 			modelType: reflect.TypeOf(bunEmployee{}),
 			parentKey: "Department",
-			want:      "dept_id",
+			want:      []string{"dept_id"},
+		},
+		{
+			name:      "bun composite join returns all local columns",
+			modelType: reflect.TypeOf(bunCompositeEmployee{}),
+			parentKey: "department",
+			want:      []string{"dept_id", "tenant_id"},
 		},
 
 		// GORM foreignKey: tag
@@ -60,19 +91,33 @@ func TestGetForeignKeyColumn(t *testing.T) {
 			name:      "gorm foreignKey resolves to column name",
 			modelType: reflect.TypeOf(gormEmployee{}),
 			parentKey: "department",
-			want:      "department_id",
+			want:      []string{"department_id"},
 		},
 		{
 			name:      "gorm foreignKey resolves second relation",
 			modelType: reflect.TypeOf(gormEmployee{}),
 			parentKey: "manager",
-			want:      "manager_id",
+			want:      []string{"manager_id"},
 		},
 		{
 			name:      "gorm foreignKey matched case-insensitively",
 			modelType: reflect.TypeOf(gormEmployee{}),
 			parentKey: "Department",
-			want:      "department_id",
+			want:      []string{"department_id"},
+		},
+		{
+			name:      "gorm composite foreignKey returns all columns",
+			modelType: reflect.TypeOf(gormCompositeEmployee{}),
+			parentKey: "department",
+			want:      []string{"dept_id", "tenant_id"},
+		},
+
+		// Join left-side scan (parentKey is a raw column name, not a relation field name)
+		{
+			name:      "self-referential: parent PK column returns child FK column",
+			modelType: reflect.TypeOf(selfRefItem{}),
+			parentKey: "rid_item",
+			want:      []string{"rid_parentitem"},
 		},
 
 		// Pointer and slice unwrapping
@@ -80,43 +125,43 @@ func TestGetForeignKeyColumn(t *testing.T) {
 			name:      "pointer to struct is unwrapped",
 			modelType: reflect.TypeOf(&gormEmployee{}),
 			parentKey: "department",
-			want:      "department_id",
+			want:      []string{"department_id"},
 		},
 		{
 			name:      "slice of struct is unwrapped",
 			modelType: reflect.TypeOf([]gormEmployee{}),
 			parentKey: "department",
-			want:      "department_id",
+			want:      []string{"department_id"},
 		},
 
-		// No tag — returns "" so caller can fall back to convention
+		// No tag — returns nil so caller can fall back to convention
 		{
-			name:      "relation with no FK tag returns empty string",
+			name:      "relation with no FK tag returns nil",
 			modelType: reflect.TypeOf(conventionEmployee{}),
 			parentKey: "department",
-			want:      "",
+			want:      nil,
 		},
 
 		// Unknown parent key
 		{
-			name:      "unknown parent key returns empty string",
+			name:      "unknown parent key returns nil",
 			modelType: reflect.TypeOf(gormEmployee{}),
 			parentKey: "nonexistent",
-			want:      "",
+			want:      nil,
 		},
 		{
-			name:      "non-struct type returns empty string",
+			name:      "non-struct type returns nil",
 			modelType: reflect.TypeOf(""),
 			parentKey: "department",
-			want:      "",
+			want:      nil,
 		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			got := GetForeignKeyColumn(tt.modelType, tt.parentKey)
-			if got != tt.want {
-				t.Errorf("GetForeignKeyColumn(%v, %q) = %q, want %q", tt.modelType, tt.parentKey, got, tt.want)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetForeignKeyColumn(%v, %q) = %v, want %v", tt.modelType, tt.parentKey, got, tt.want)
 			}
 		})
 	}