QSqlQuery::executedQuery () -- Bound values versus place holders

[davethomaspilot]

After doing an insert to a local MySql database, I want to log the SQL text to a file and use it later for inserting to a different ( remote) database when a connection is available.

The docs for QSqlQuery::executedQuery () say:

The placeholders in the original query are replaced with their bound values to form a new query.

But, for an insert, I see "?" for all the values :

"INSERT INTO TEAM_RECORDS (event_id, race, heat, today, left_team_time, left_start_time, left_result, right_team_time, right_start_time, right_result) VALUES ( ?,?,?,?,?,?,?,?,?,?)"

I also tried QSqlQuery::lastQuery, but the Sql text has the placeholders, not the values:

"INSERT INTO TEAM_RECORDS (event_id, race, heat, today, left_team_time, left_start_time, left_result, right_team_time, right_start_time, right_result) VALUES ( :event_id,:race,:heat,:today,:left_team_time,:left _start_time,:left_result,:right_team_time,:right_s tart_time,:right_result)"

Is this the intended behavior?

I can write a little code to parse the SQL returned by ::lastQuery and replace the placeholders with values from the bindValues, but thought I'd ask if I might be missing something already in the class.

[ChrisW67]

This "placeholders in the original query are replaced with their bound values to form a new query." only occurs if "a prepared query with placeholders is executed on a DBMS that does not support it". Otherwise, as the docs say, this generally returns the same as lastQuery() because Qt never builds a query string with the values replaced in that case.

I can write a little code to parse the SQL returned by ::lastQuery and replace the placeholders with values from the bindValues, but thought I'd ask if I might be missing something already in the class.

Why would you want to do that? You can certainly make a much better error or log message than to simply dump the equivalent raw SQL (which you will have to be careful to escape correctly).

[davethomaspilot]

I don't want a human readable message. I wanted the actual Sql command with values substituted so it could be used directly to insert into another database.

I just wrote the code to build use the SQL for the "prepare" and the key/value pairs from the bind values. Encapsulated in xml and then parse in remote server that uses it.

It all works--I just thought it would be simpler to have SQL with the values substituted rather than the additional complexity.

Thanks,

Dave Thomas

[wysota]

I think it would make more sense to use some standard replication scheme.

E.g.: http://dev.mysql.com/doc/refman/5.0/en/replication.html

[davethomaspilot]

This is definitely the way to go. Use MySql replication rather than "roll your own".

I needed to read the docs a couple of times to get comfortable with the configuration process. It sounded much more complicated than what it really is.

Thanks for the good advice!

Works great on servers that I can admin. Now, I either need to change web hosting services to get one that will allow me to configure a mysql server, or figure out to encapsulate the equivalent of the bin-log files into something I can do an http post with.

Thanks!

Dave Thomas