incorrect namespace about data

[kamarton]

and \Yiisoft\Data\Reader\OffsetableDataInterface: mongodb support inserting at position (see $position). I can imagine that there is an API endpoint that can write to a position similarly.

[samdark]

While such SQL makes sense, I see no use for filtering in case of writer. We have data we want to write already, it's easier and more efficient to filter data with simple foreach than by passing unfiltered data array to writer along with saving criteria.

[rob006]

Example SQL update:

This looks like MySQL-specific. AFAIK limit and order are not directly supported in update queries by most of DBMS.

[kamarton]

@rob006 This is a generic Writer layer, if you have the opportunity somewhere, it is advisable to plan into the layer.

[samdark]

I still don't see any practical application for using filters with a data writer. We have our data, we can prepare it right away before sending it to writer. That has both simplicity and performance benefits.

[kamarton]

I can't really see what the Writer interface is all about. I assumed that ActiveRecord would use this too, hiding the write layer, e.g. so that I can swap one NoSQL under it for another NoSQL without changing ActiveRecord class.

$ar->field2 = '22';
$ar->save();

// $ar->save() --> $db->writer() -> writer->write();
$db->writer->withFilters(new Equals('id',  $ar->id))->write($ar->changedAttributes());

I implemented more database server under yii2, and I find this solution easier to implement and more flexible.

[samdark]

I can't really see what the Writer interface is all about.

Having array of data items, persist all of them:

$data = [
    [
        'id' => 1,
        'name' => 'Somogyi',
    ],
    [
         'id' => 2,
         'name' => 'Alex',
    ],
];

$writer = new ActiveRecordDataWriter(User::class);
$writer->write($data);

$db->writer->withFilters(new Equals('id', $ar->id))->write($ar->changedAttributes());

Why do you need withFilters here? Also, changed attributes isn't writer concern. That's internal thing of a possible AR specific implementation.

[kamarton]

It's ok, if run INSERT, but if require UPDATE?

$writer = new ActiveRecordDataWriter(User::class);
$writer->write($data);

I don't really see why Writer filters are provided wit AR, whereas Reader filters are not.

$db->writer->withFilters(new LessThan('id',  88))->write($attributes);
// === yii2 AR->updateAll($attributes, ['<', 'id', 88]);

If I use simple types, I just need to replace the Writer and write to almost any target destination (RDBMS, NoSQL, Redis), eg with custom BasicActiveRecord. If ActiveRecord does this (why?), Then I need to create a N versions of class because they must extends from different classes.

Nonetheless, I already understand that this is not a real Writer layer, but some very simplified implementation, and I probably need to see the rest of the system to understand why.

[samdark]

Yes, that wasn't meant to replace AR or provide full-featured abstraction over any storage. Let's assume it won't be needed to reuse filters for writer.