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Thread: SQL module and Thread-safe

  1. #1
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    Default SQL module and Thread-safe

    I have database object in my mainthread (GUI).

    I must do a lot of insert statement so I want to do this in other thread.
    Can I create QSqlQuery in other(not main) thread and execute a lot of inserts?
    QSqlQuery use database object which is created in main thread.
    In QT doc is write that qt database object should not be used in other thread, so how can I start transaction in other thread?


    I cant create second connection object in second thread because I use firebird embedded database.


    sory for my poor english

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    Default Re: SQL module and Thread-safe

    I'am interessted in this too.

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    Default Re: SQL module and Thread-safe

    http://doc.qt.nokia.com/4.6/threads-...the-sql-module

    You can use the sql module in a different thread than your main GUI thread.
    BUT!!! You have to keep everything in one thread. You can not create the database in thread 1 and do a query in thread 2.

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    Default Re: SQL module and Thread-safe

    so when I use firebird embedded I cant write mutlithread program.

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    Default Re: SQL module and Thread-safe

    Multithreaded program: yes (you can have a database manager in a separate thread)
    Using multiple threads for the sql classes: no

    There's no reason to do that either since most databases are optimized to work in a certain way.

    If you want to add lots of data at the same time in a database, don't do this query by query. Start a transaction, fill the transaction buffer and then commit it in one go.

  6. #6
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    Default Re: SQL module and Thread-safe

    Firebird team release 2.5RC3 version.
    In release note we can read:

    "The client libraries, including the embedded one, can now be used in multi-threaded applications without any application-level synchronization."

    so with this library can I use Qt sql classes (with one connection) in more than one thread?

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    Default Re: SQL module and Thread-safe

    No.

    This has nothing to do with the used database, but everything with Qt.

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