SQLITE ATTACH database

Is it possible to attach an SQLITE database and still use the Qt database classes?

Well, you could use the sql statement

Code:

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ATTACH DATABASE filename AS databasename

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then it is pure SQL and has nothing to do with Qt. => You can still use Qt's classes.

Or you can simply use

Code:

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QSqlDatabase::addDatabase("path/to/file", "mySecondDatabase");
//...
QSqlQuery q(QSqlDatabase::database("mySecondDatabase"));

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Quote:

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Originally Posted by Lykurg

Well, you could use the sql statement

Code:

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ATTACH DATABASE filename AS databasename

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then it is pure SQL and has nothing to do with Qt. => You can still use Qt's classes.

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Thanks. I was not sure if that method would work.

Quote:

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Or you can simply use

Code:

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QSqlDatabase::addDatabase("path/to/file", "mySecondDatabase");
//...
QSqlQuery q(QSqlDatabase::database("mySecondDatabase"));

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Now that I expected to work.


Now the question is mainly can I use 2 databases in the same QSqlQuery? I assume with the ATTACH database sql statement I can do this.

Hello all!

Regarding the same subject.

It is possible to attach a database that resides into a QTemporaryFile?

Thank you!

Quote:

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Originally Posted by tavioman

It is possible to attach a database that resides into a QTemporaryFile?

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Have you tried? Why shouldn't it working? It's a "normal" file. Just use QTemporaryFile::fileName() to work with the file.

Quote:

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Originally Posted by drescherjm

Now the question is mainly can I use 2 databases in the same QSqlQuery? I assume with the ATTACH database sql statement I can do this.

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with Qt classes you need add two databases using QSqlDatabase::addDatabase, but you need specify different connectionName:

Code:

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QSqlDatabase db1 = QSqlDatabase::addDatabase("QSQLITE", "db1");
db1.setDatabaseName("path/to/db1");
QSqlDatabase db2 = QSqlDatabase::addDatabase("QSQLITE", "db2");
db2.setDatabaseName("path/to/db2");
//opening databases and etc.

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then you can get data from these databases like this:

Code:

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...
QSqlDatabase db1 = QSqlDatabase::database("db1");
QSqlDatabase db2 = QSqlDatabase::database("db2");
 
QSqlQuery query1(db1);
//preparing query and execution
...
QSqlQuery query2(db2);
//preparing query and execution
...

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Quote:

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Originally Posted by Lykurg

Or you can simply use

Code:

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QSqlDatabase::addDatabase("path/to/file", "mySecondDatabase");
//...
QSqlQuery q(QSqlDatabase::database("mySecondDatabase"));

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are you sure that your code will work?
the first parameter of QSqlDatabase::addDatabase should be a name of a driver? i.e. should be:

Code:

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QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE", "mySecondDatabase");
db.setDatabaseName("path/to/file");
 
//...
QSqlQuery q(QSqlDatabase::database("mySecondDatabase"));

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Quote:

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Originally Posted by spirit

are you sure that your code will work?

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Of course not, it was a typo, but since drescherjm figured it out himself...

And I just wonder, why people often ask questions like "Is fooBar working?" without trying it themself before asking. Then they would realize, that it is working.

Quote:

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Originally Posted by Lykurg

And I just wonder, why people often ask questions like "Is fooBar working?" without trying it themself before asking. Then they would realize, that it is working.

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agree w you. :)