Add method batchUpdate in \yii\db\QueryBuilder about db

[samdark]

Looks like a good idea. Further research on how to do it in MSSQL, Oracle and SQLite is needed to move forward to implementing it.

[bscheshirwork]

@dimmitri good idea. So... I see some indeterminate stages: how to get inserted ids? How to separate inserted and updated rows?

[dimmitri]

I think it is necessary to first look at ALL the options implemented in different DBMS. To identify common features. In PostgreSQL in at least two ways to do it, in MySQL I know of one, but maybe more of them. I've never used MSSQL, Oracle and SQLite.

How to separate inserted and updated rows?

PostgreSQL. In this case, for example, insert is not happening:

UPDATE table AS t
SET
    col1 = c.col1,
    col2 = c.col2
FROM (VALUES (1, 1, 1), (2, 2, 2), (3, 3, 3), (4, 4, 4) ) AS c (id, col1, col2)
WHERE c.id = t.id;

[Vovan-VE]

in MySQL I know of one, but maybe more of them

In MySQL UPDATE with JOIN can be used for example. Something like this:

UPDATE `table` AS `t` 
    JOIN (
        SELECT 1 AS `id`, 1 AS `col1`, 1 AS `col2`
        UNION SELECT 2, 2, 2
        UNION SELECT 3, 3, 3
    ) AS `c`
        ON `t`.`id` = `c`.`id`
SET
    `t`.`col1` = `c`.`col1`,
    `t`.`col2` = `c`.`col2`;

[bscheshirwork]

@Vovan-VE
i.e. need
n subquery + 1 query
vs
n query
if you can directly update row-by-row?

[Tigrov]

Related with #67 perhaps double.
Looks like need batchUpsert() for both issues.