CODEWITHSUNDEEP
c++qtqt4concatenationqstring
RicoRicochet
RicoRicochet

Reputation: 2289

Concatination of "a set strings" and "input from QLineEdit" into a QString

I am writing a GUI application which will perform select * from table_name from an oracle database and populate the result in a TableView Model. To take my query as an input for querying the database I have used---

QString MyQuery = ui->lineEdit->text();
QSqlQuery query(MyQuery,db);

and it works perfectly.

Now I want to optimize it by making the user type only the table_name as an input in the lineEdit. The program will perform select * from table_name on it by itself.

So I think I need to store "SELECT * FROM " in the QString variable and concatinate the input from lineEdit to it.

I am not much sure about the syntax of this concatination so both of my tries---

    QString myquery;
    strcat(myquery,"SELECT * FROM ");
    strcat(myquery,ui->lineEdit );

and,

    QString myquery = "SELECT * FROM " + ui-lineEdit->text();

have resulted in build errors. Any suggestions on how to perform the desired concatination ???

Upvotes: 2

Views: 513

Answers (2)

Nejat
Nejat

Reputation: 32655

You can use QSqlTableModel to show a table contents in a QTableView :

QSqlTableModel * model = new QSqlTableModel(this,db);
model->setEditStrategy(QSqlTableModel::OnFieldChange);
model->setTable( "someTable" );
model->select();

ui->tableView->setModel( model );

But in case you want to use QSqlQuery you can make the query like :

String myquery = QString("SELECT * FROM %1").arg(ui->lineEdit->text());

Or even better:

query.prepare("SELECT * FROM :tableName");
query.bindValue(":tableName", ui->lineEdit->text());

Upvotes: 4

thuga
thuga

Reputation: 12931

You can use QString::arg to add arguments to a string.

For example:

QString input = ui->lineEdit->text();
QString myQUery = QString("SELECT * FROM %1").arg(input);

Upvotes: 3

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