orm: add references attribute to allow foreign key declarations on …

…fields (#19349)

cmd/tools/vtest-self.v

@@ -135,6 +135,7 @@ const (
 		'vlib/orm/orm_result_test.v',
 		'vlib/orm/orm_custom_operators_test.v',
 		'vlib/orm/orm_fk_test.v',
+		'vlib/orm/orm_references_test.v',
 		'vlib/db/sqlite/sqlite_test.v',
 		'vlib/db/sqlite/sqlite_orm_test.v',
 		'vlib/db/sqlite/sqlite_vfs_lowlevel_test.v',
@@ -162,6 +163,7 @@ const (
 		'vlib/orm/orm_create_and_drop_test.v',
 		'vlib/orm/orm_insert_test.v',
 		'vlib/orm/orm_insert_reserved_name_test.v',
+		'vlib/orm/orm_references_test.v',
 		'vlib/v/tests/websocket_logger_interface_should_compile_test.v',
 		'vlib/v/tests/orm_sub_array_struct_test.v',
 		'vlib/v/tests/orm_handle_error_for_select_from_not_created_table_test.v',
@@ -171,6 +173,7 @@ const (
 		'vlib/orm/orm_create_and_drop_test.v',
 		'vlib/orm/orm_insert_test.v',
 		'vlib/orm/orm_insert_reserved_name_test.v',
+		'vlib/orm/orm_references_test.v',
 		'vlib/v/tests/orm_sub_array_struct_test.v',
 		'vlib/v/tests/orm_handle_error_for_select_from_not_created_table_test.v',
 		'vlib/v/tests/project_with_cpp_code/compiling_cpp_files_with_a_cplusplus_compiler_test.v', // fails compilation with: undefined reference to vtable for __cxxabiv1::__function_type_info'
@@ -215,6 +218,7 @@ const (
 		'vlib/orm/orm_result_test.v',
 		'vlib/orm/orm_custom_operators_test.v',
 		'vlib/orm/orm_fk_test.v',
+		'vlib/orm/orm_references_test.v',
 		'vlib/v/tests/orm_sub_struct_test.v',
 		'vlib/v/tests/orm_sub_array_struct_test.v',
 		'vlib/v/tests/orm_joined_tables_select_test.v',

vlib/orm/orm.v

@@ -463,6 +463,8 @@ pub fn orm_table_gen(table string, q string, defaults bool, def_unique_len int,
 		mut is_unique := false
 		mut is_skip := false
 		mut unique_len := 0
+		mut references_table := ''
+		mut references_field := ''
 		mut field_name := sql_field_name(field)
 		mut ctyp := sql_from_v(sql_field_type(field)) or {
 			field_name = '${field_name}_id'
@@ -512,6 +514,31 @@ pub fn orm_table_gen(table string, q string, defaults bool, def_unique_len int,
 						default_val = attr.arg
 					}
 				}
+				'references' {
+					if attr.arg == '' {
+						if field.name.ends_with('_id') {
+							references_table = field.name.trim_right('_id')
+							references_field = 'id'
+						} else {
+							return error("references attribute can only be implicit if the field name ends with '_id'")
+						}
+					} else {
+						if attr.arg.trim(' ') == '' {
+							return error("references attribute needs to be in the format [references], [references: 'tablename'], or [references: 'tablename(field_id)']")
+						}
+						if attr.arg.contains('(') {
+							ref_table, ref_field := attr.arg.split_once('(')
+							if !ref_field.ends_with(')') {
+								return error("explicit references attribute should be written as [references: 'tablename(field_id)']")
+							}
+							references_table = ref_table
+							references_field = ref_field[..ref_field.len - 1]
+						} else {
+							references_table = attr.arg
+							references_field = 'id'
+						}
+					}
+				}
 				else {}
 			}
 		}
@@ -541,6 +568,9 @@ pub fn orm_table_gen(table string, q string, defaults bool, def_unique_len int,
 			f += ')'
 			unique_fields << f
 		}
+		if references_table != '' {
+			stmt += ' REFERENCES ${references_table} (${references_field})'
+		}
 		fs << stmt
 	}
 

vlib/orm/orm_references_test.v

@@ -0,0 +1,33 @@
+import db.sqlite
+
+struct Boat {
+	id          int [primary; sql: serial]
+	color_id    int [references]
+	another1_id int [references: 'size']
+	another2_id int [references: 'size(secondary_id)']
+}
+
+struct Color {
+	id  int    [primary; sql: serial]
+	hex string
+}
+
+struct Size {
+	id           int [primary; sql: serial]
+	secondary_id int
+}
+
+fn test_references_constraint() {
+	db := sqlite.connect(':memory:') or { panic(err) }
+
+	sql db {
+		create table Boat
+		create table Color
+		create table Size
+	} or { panic(err) }
+
+	// this pragma returns a row for each foreign key constraint on a table
+	pragma_result := db.exec('pragma foreign_key_list(boat)') or { panic('nope') }
+
+	assert pragma_result.len == 3
+}