It is more simple and more accurate

Checking that the platform supports foreign key is not the right case
here, because we should check if we can create them by themselves, after
the table is created. It is not the case for Sqlite.

Closes #3990

Upstream libs and tools have improvements that make them unnecessary.

This will allow to omit parameters with unspecified types

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

also simplifies the code and now exactly matches postgresql search rules

When the connection is lost or is closed, subsequent transaction will no longer be nested because they started in a brand new session. Our internal representation of the nesting shold take this into account

Internally, ArrayStatement expects every row to be represented as an array regardless of the fetch mode, however FetchMode::COLUMN produces one value per row.

The failures are caused by the changes in PHP according to https://wiki.php.net/rfc/notice-for-non-valid-array-container.