user3136871 user3136871 - 1 month ago 18
C++ Question

Qt QSqlQuery bindValue works with ? but not with :placeholders

I'm working with SQLite, doing insert into table. Folowwing

QSqlQuery testQuery(QString("INSERT INTO test(testcol) VALUES(?)"));
testQuery.bindValue(0, someQStringObg);
testQuery.exec();


works, but

QSqlQuery testQuery(QString("INSERT INTO test(testcol) VALUES(:val)"));
testQuery.bindValue(":val", someQStringObg);
testQuery.exec();


don't. testQuery.lastError().text() returns No query Unable to fetch row

Have no clue why things are that way, but really want to find out.

Answer

Please use prepare as the official example:

QSqlQuery testQuery;
testQuery.prepare("INSERT INTO test(testcol) VALUES(:val)");
testQuery.bindValue(":val", someQStringObj);
testQuery.exec();

The reason for the error is that the query was executed before binding to the corresponding placeholder. You can see the relevant part of the constructor documentation:

If query is not an empty string, it will be executed.

Comments