Insert ID semantics

[mindplay-dk]

The Connection interface of the library (like most DB libraries in PHP) currently mirrors the poor semantics of PDO::lastInsertId(), in which obtaining an auto-generated ID is dependent on the order in which e.g. Connection-methods are invoked; e.g. requiring you to ask for the generated ID immediately after executing an INSERT query.

INSERT .. RETURNING under Postgres has the correct semantics, in which you have to specify up-front (before executing the query) that you need a generated ID - in other words, it's not depedent on execution order.

The library should mirror Postgres semantics by requiring you to specify up-front what you need, which means the driver and query builder architecture need to be extended to support this, which will require breaking changes.

[mindplay-dk]

The library should mirror Postgres semantics by requiring you to specify up-front what you need, which means the driver and query builder architecture need to be extended to support this

This was attempted and found non-feasible with the MySQL PDO driver, which supports multiple-insert, but provides no means of obtaining more than one generated key afterwards - as opposed to Postgres, which supports the RETURNING clause.

In other words, this would work only for single-insert under MySQL, so the situation either way, is that differences in functionality cannot be mediated without substantial trade-offs, e.g. lowest common denominator.

Since the goal for this library is not to abstract differences between DBMS, but rather to allow DBMS-specific features to be leveraged, I will not pursue this issue any further at this time.

Suffice it to say, the differences could be mediated, by avoiding PDO, and instead building a suitable driver model based on the postgres and mysqli extensions, but this is way beyond the scope of this project, at this time.