Avoiding sp_cursorfetch with QSqlxxxx

  • I have an app that uses a QSqlDatabase connecting to an MS SQL Server through ODBC.
    I noticed, that all classes available for data retrieval (like QSqlQuery, QSqlQueryModel, QSqlTableModel) use sp_cursorfetch.

    Isn't there a way to just retrieve the whole table at once, or at least specify the batch size?
    I'm trying to do some processing on each row of the data, and I end up making too many calls to the database

    • if I use QSqlQuery.next(), I get a call to the database every time I call next()
    • if I use QSqlQueryModel I have to use something like: while canFetchMore() fetchMore in order to get the data (which is again numerous calls to the database)

  • Are you sure QSqlQuery.next() get a call to the database? I think next() retrieve the next row from a prevent exec()

  • Yes, I am very sure....
    I get a call for every next() call.
    The output from SQL Server profiler is like this:

    1) exec sp_cursoropen ....

    2) exec sp_cursorfetch 180150003,1,0,1

    3) exec sp_cursor 180150003,40,1

    4) Repeat 2) and 3) for each record returned by the query

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