I find Yii2 documentation seriously lacking in documentation about i18n, particularly about using database instead of files for the translation messages.
I see documentation (EDIT: sorry, this was the link I meant) mentions the DbMessageSource class and somewhere else I found that the db tables should be named source_message and message but nowhere does it tell me the schema for those tables! And the yii message/extract command doesn't seem to auto-create the tables either.
How do I go about this?
Your documentation link is about a yii2 extension, you should read instead :
If you don't want to use migration and need SQL instead, files for all databases are in migrations directory.
https://github.com/yiisoft/yii2/tree/master/framework/i18n/migrations
For example, the schema for MySQL is :
CREATE TABLE `source_message`
(
`id` integer NOT NULL AUTO_INCREMENT PRIMARY KEY,
`category` varchar(255),
`message` text
);
CREATE TABLE `message`
(
`id` integer NOT NULL,
`language` varchar(16) NOT NULL,
`translation` text
);
ALTER TABLE `message` ADD CONSTRAINT `pk_message_id_language` PRIMARY KEY (`id`, `language`);
ALTER TABLE `message` ADD CONSTRAINT `fk_message_source_message` FOREIGN KEY (`id`) REFERENCES `source_message` (`id`) ON UPDATE CASCADE ON DELETE RESTRICT;
The
source_messagetable stores the messages to be translated, and themessagetable stores the translated messages. The name of these two tables can be customized by setting$sourceMessageTableand$messageTable, respectively.