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Thread: How to create an One-to-Many Relationship in QtSqlRelation ?

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    Default How to create an One-to-Many Relationship in QtSqlRelation ?

    Hi All,
    I've a problem when I aim to view data into QTableView. I aim to create an One-to-Many (OTM) Relationship in QtSqlRelation. the code can I do is one-to-one like this, I've no Idea for the OTM. How should it be ?.
    Qt Code:
    1. model->setTable("Users");
    2. model->setSort(User_Id, Qt::AscendingOrder);
    3. model->setHeaderData(User_Name,Qt::Horizontal,tr("Username"));
    4. model->setHeaderData(User_FirstName, Qt::Horizontal, tr("First name"));
    5. model->setHeaderData(User_LastName, Qt::Horizontal, tr("Last Name"));
    6. model->setRelation(User_Mode,QSqlRelation("UserModes","ID","Name"));
    7. model->setHeaderData(User_Mode, Qt::Horizontal, tr("Type"));
    8. model->select();
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    Thanks

    Hary

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    Default Re: How to create an One-to-Many Relationship in QtSqlRelation ?

    The code above doesn't determine if the relation between Users and UserModes is 1-1 or 1-n. You may have several users with the same user mode (1-n) with the code above.
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

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  3. The following user says thank you to wysota for this useful post:

    innobleday (13th March 2010)

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    Default Re: How to create an One-to-Many Relationship in QtSqlRelation ?

    Quote Originally Posted by wysota View Post
    The code above doesn't determine if the relation between Users and UserModes is 1-1 or 1-n. You may have several users with the same user mode (1-n) with the code above.
    Firstly I'm not sure with my code.. Sorry if I miss understanding about 1-n. But the problem is I aim to take several record of several filed in some SQL table called from another Table. In other words, in userMode containf field ID, level1, level2 etc.. and I just want to take level1 level2.. the ID is used to relation between users and usermode. How shoild it be? thaks.

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    Default Re: How to create an One-to-Many Relationship in QtSqlRelation ?

    I'm afraid I don't understand what you mean. If you want to join two tables then that's not possible with QSqlRelationalTableModel. You can only substitute data from a column with data from some column from another table. To do more complex things you have to use QSqlQueryModel.
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

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