Serial fields already have a default value. By opting out of `notnull`
serial fields will just set the next value in the sequence.

I know, this is REALLY nasty but that was the only way I've found to
make it work properly.

And then we don't need to wait till v3 to not require comments on the
JsonType.

statements in a rewindable iterator. Skipped the test for iterating
multiple times with a message regarding that iterators are non
rewindable.

Only added to mysqli for now, can add to other drivers (assuming they
support reseting the pointer in some way) after feedback.

I don't really understand the mysqli driver too much and the changes
break the tests so undo using an iterator for this particular driver.

Allows result sets to be iterated over without running out of memory on
large data sets.

It is a somewhat fragile thing to do.

It groups things naturally.

I think distinguish was the intended meaning here, not dismantle.

Added upgrade notice about BC break.
Cleanups

Changed DBALException::invalidPlatformSpecified() exception to be more detailed about what was given.

Replaced the code examples for `set()` to show that the value parameter is not escaped and thus could pose an SQL injection vulnerability.

In a few cases methods in Connection may throw a DBALException which
isn't declared in the docblock. As the Connection class is heavily
used by third party code, this code runs the risk of ignoring
those exceptions instead of handling them. While it is
technically not required to declare exceptions in PHP, it is highly
recommended, especially in public APIs.