string lastInsertId(string name);
Returns the ID of the last inserted row, or the last value from a sequence object, depending on the underlying driver. For example, PDO_PGSQL() requires you to specify the name of a sequence object for the name parameter.
This method may not return a meaningful or consistent result across different PDO drivers, because the underlying database may not even support the notion of auto-increment fields or sequences.
If a sequence name was not specified for the name parameter, PDO->lastInsertId() returns a string representing the row ID of the last row that was inserted into the database.
If a sequence name was specified for the name parameter, PDO->lastInsertId() returns a string representing the last value retrieved from the specified sequence object.
If the PDO driver does not support this capability,
PDO->lastInsertId() triggers an