correctly documented API for mysql FOUND_ROWS

[Mathieu Lacage]

Hi,

The mysql connector sets by default the FOUND_ROWS bit in the client_flag set on each connection with the server. The documentation is explicit about this (good): http://docs.sqlalchemy.org/en/rel_0_9/dialects/mysql.html#rowcount-support

However, the documentation also says that it is possible to override this setting through the client_flag url argument. While it is indeed possible to set manually this client_flag argument, the FOUND_ROWS bit is set unconditionally in dialects/mysql/mysqlconnector.py

Hence, the attached patch (generated against git master) to allow callers who know what they are doing to override this default behavior in sqlalchemy

[Mike Bayer]

I'd rather just change the docs to state that this is not an option. the FOUND_ROWS flag has no point in being changed IMHO.

also, both mysqldb and mysqlconnector have a try/except around the whole operation, in the case of mysqldb this is probably due to very ancient versions of mysqldb and in the case of mysqlconnector I dont think there is any valid case for an except: there. The try/except should be removed.

For the case where you really want to be able to affect this, I'd prefer an explicit option create_engine(..., count_matched_rows=True) that works equally for mysqldb, mysqlconnector, oursql, and the others (or raises a NotImplementedError for a DBAPI that doesn't provide for it). I'd need a pull request with unit tests for this.

[Mike Bayer]

• mention that FOUND_ROWS is hardcoded; fixes #3146

→ <<cset 9f66e75ea71f>>

[Mike Bayer]

• mention that FOUND_ROWS is hardcoded; fixes #3146

→ <<cset a16ee423e452>>

[Mike Bayer]

• mention that FOUND_ROWS is hardcoded; fixes #3146

→ <<cset c149e020cbeb>>

[Mike Bayer]

see https://bitbucket.org/zzzeek/sqlalchemy/issue/3173/add-count_matched_rows-api-for-all-mysql for feature add