Revision #5 was created by grigori on Nov 25, 2019, 10:35:47 PM.
fixing the markup
Content
> I have a dream ...
I am happy to join with you today in what will go down in history as the greatest demonstration of ...
bad design of Active Record.
I have an API. It's built with a RESTestful extension over Active Record, and some endpoints provide PUT methods to upload files. By a REST design we create an entity with `POST /video` first, and then upload a video file with `PUT /video/{id}/data`.
How do we get the `{id}`? The essential solutuion is UUID generated by a client. It allows API application to be stateless and scale it, use master-master replication for databases and feel yourself a modern guy.
If you have Poistgres - lucky you, feel free to use the built-in UUID data type and close this article.
With MySQL the essential solution is [insert into users values(unhex(replace(uuid(),'-',''))...](https://mysqlserverteam.com/storing-uuid-values-in-mysql-tables/)
MySQL team recommends updating our INSERT queries. With Active Record it is not really possible.
[...]
If you design the application from ground up, you can use defferent fields for a binary and text representation of UUID, and reference them in different parts of an application, but I am bound to the legacy code.
Adding `getId()`/`/setId()` won't help - data comes from a client in JSON and fills the model object with a `setAttributes()` call avoiding generic magic methods.
Here's the hack:
1.Step 1 add a `private $idText;` property
St2. add two filters
```php
['id','match', 'pattern'=>'/^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i'],
// convert UUID from text value to binary and store the text value in a private variable
// this is a workaround for lack of mapping in active record
['id','filter','skipOnError'=>true, 'filter'=>function($uuid){
$this->idText = $uuid;
return pack("H*", str_replace('-', '', $uuid));
}],
```
These filters will validate input, prepare UUID to be written in a binary format and keep the text form for output.
Step 3. Add getters
```php
public function __get($name)
{
[...]
From the other hand, the first valiator calls `$model->id` triggering the getter before the UUID is saved to the private property so I need to serve the value from user input.
It is strange to mutate data in a validator, but I found this is the only solution. I belive I shouldn't use `beforeSave()` callback to set the binary value for SQL, and return the text value back in `afterSave()`, supporting this code later will be a hell.
So, now you can go the generic MySQLmysql way
Step 4. add a virtual column
```sql
ALTER TABLE t1 ADD id_text varchar(36) generated always as
(insert(
[...]
24,0,'-')
) virtual;
```
Step 5. Use Object Relation Mapping in Yii 3 when it's available and write siple mapping instead.