Python MYSQLdb documentation missing details?

问题:

I am trying to make sense of MySQLdb documentation. I was just wondering if there are things missing from there. For example, I am trying to see what "rowcount" (a constant) actually does, but am not seeing it anywhere in the documentation.

So is the documentation incomplete or am I just looking at the wrong place?

Thanks.

回答1:

The primary source of documentation for Python database modules is the DB-API 2.0 specification:

.rowcount 

       This read-only attribute specifies the number of rows that
        the last .execute*() produced (for DQL statements like
        'select') or affected (for DML statements like 'update' or
        'insert').

       The attribute is -1 in case no .execute*() has been
        performed on the cursor or the rowcount of the last
        operation is cannot be determined by the interface. [7]

       Note: Future versions of the DB API specification could
        redefine the latter case to have the object return None
        instead of -1.

回答2:

I found this tutorial on MySQLDB useful. Rowcount is mentioned, but not used in one of the examples.

回答3:

Well after poring through the source code, here's the relevant line (MySQLdb/cursors.py:120)

self.rowcount = db.affected_rows()

So rowcount is just a member variable for the Cursor class (not a method), which happens to hold the result of affected_rows. I guess it probably saves you a call to that particular function.

回答4:

I used the following google search: rowcount site:mysql-python.sourceforge.net

It is often better to use google site: operator to search a site than to use the site's native search. But your right, it doesn't have it's own documentation.