orm: do not order by default, ordering is slow; also fix a bug for tables without defined primary keys

vlib/orm/orm.v

@@ -272,13 +272,12 @@ pub fn orm_select_gen(orm SelectConfig, para string, num bool, qm string, start_
 		}
 	}
 
-	str += ' ORDER BY '
+	// NB: do not order, if the user did not want it explicitly,
+	// ordering is *slow*, especially if there are no indexes!
 	if orm.has_order {
+		str += ' ORDER BY '
 		str += '$para$orm.order$para '
 		str += orm.order_type.to_str()
-	} else {
-		str += '$para$orm.primary$para '
-		str += orm.order_type.to_str()
 	}
 
 	if orm.has_limit {

vlib/orm/orm_fn_test.v

@@ -51,7 +51,7 @@ fn test_orm_select_gen() {
 		fields: get_select_fields()
 	}, "'", true, '?', 0, orm.QueryData{})
 
-	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' ORDER BY 'id' ASC;"
+	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table';"
 }
 
 fn test_orm_select_gen_with_limit() {
@@ -61,7 +61,7 @@ fn test_orm_select_gen_with_limit() {
 		has_limit: true
 	}, "'", true, '?', 0, orm.QueryData{})
 
-	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' ORDER BY 'id' ASC LIMIT ?0;"
+	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' LIMIT ?0;"
 }
 
 fn test_orm_select_gen_with_where() {
@@ -75,7 +75,7 @@ fn test_orm_select_gen_with_where() {
 		is_and: [true]
 	})
 
-	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' WHERE 'abc' = ?0 AND 'test' > ?1 ORDER BY 'id' ASC;"
+	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' WHERE 'abc' = ?0 AND 'test' > ?1;"
 }
 
 fn test_orm_select_gen_with_order() {
@@ -96,7 +96,7 @@ fn test_orm_select_gen_with_offset() {
 		has_offset: true
 	}, "'", true, '?', 0, orm.QueryData{})
 
-	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' ORDER BY 'id' ASC OFFSET ?0;"
+	assert query == "SELECT 'id', 'test', 'abc' FROM 'test_table' OFFSET ?0;"
 }
 
 fn test_orm_select_gen_with_all() {