QSqlite in QT4

[sophister]

I am trying to use QSqlite in my QT project.
according to the QT assistant, I use the QSqlquery to insert data into database, but failed!!
Here's my code:
QSqlQuery insert(db);
insert.exec("select * from Person");
int num = insert.size();
if( !insert.isActive())
QMessageBox::information(this, "Query not activited", "Sorry but this query is not activited!");
bool ok = insert.exec( QString("insert into Person values (%1, \'%2\', \'%3\', %4)").arg(num + 1).arg(name).arg(sex).arg(age));

Plz tell me how to make it if anybody know it.
Thanks!!

[JhonJames]

Hi!

It's: %4, %1, %2, %3

With '%' before digits.

[mcosta]

1) The formatting is wrong: "1%" instead of "%1"

2) You open the database before use QSqlQuery?

For Example

QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(dbName);
db.open();

QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(dbName);
db.open();

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3) Using "tr" in QUERY string it's dangerous (wrong). You must not translate queries.

[sophister]

Thanks, I do open the database before using QSqlQuery.
I want to insert some virables into the table. If I don't use tr, how can I insert the virables then??
My platform is XP.

[sophister]

thanks, I have corrected it.
But now what do trouble me is how to insert data into the table.
It's really difficult.

[mcosta]

I want to insert some virables into the table. If I don't use tr, how can I insert the virables then??

insert.exec( QString("insert into Person values (%4, \'%1\', \'%2\', %3)").arg(num + 1).arg(name).arg(sex).arg(age))

insert.exec( QString("insert into Person values (%4, \'%1\', \'%2\', %3)").arg(num + 1).arg(name).arg(sex).arg(age))

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Pay attention to values type. I think "name" and "sex" are strings.

[sophister]

I find some guides to SQLite, whick say that we can use the following code to insert data into one table----

insert into table_name values(data1, data2, data3, ...);


But when I use it, the application just cannot do that successfully.

[mcosta]

I edited my previous post.

The problem is that some values are strings (name and sex); in this case you have to wrap with ''

insert.exec( QString("insert into Person values (%4, \'%1\', \'%2\', %3)").arg(num + 1).arg(name).arg(sex).arg(age))

insert.exec( QString("insert into Person values (%4, \'%1\', \'%2\', %3)").arg(num + 1).arg(name).arg(sex).arg(age))

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[mcosta]

I edited my previous post.

The problem is that some values are strings (name and sex); in this case you have to wrap with ''

insert.exec( QString("insert into Person values (%4, \'%1\', \'%2\', %3)").arg(num + 1).arg(name).arg(sex).arg(age))

insert.exec( QString("insert into Person values (%4, \'%1\', \'%2\', %3)").arg(num + 1).arg(name).arg(sex).arg(age))

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__________________

[sophister]

yeah, you guess it!!
I really appreciate your help!!!
I successfully insert the values into the table.

But just one problem, the "age"'s type is int, how can I insert it into the table?

[JhonJames]

Like strings... But without ' ':

... QString("INSERT INTO table VALUES ( %1, %2 )").arg( int1 ).arg( int2 ) ...

... QString("INSERT INTO table VALUES ( %1, %2 )").arg( int1 ).arg( int2 ) ...

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Note:
String, date with ' '.
Double, float, integer: without ' '.

[sophister]

you see, when I show the table in the QTextEdit, the INTEGER cannot display appropriately.

I use the following code to display the int age---
age = query.value(3).toInt();

Where am I wrong??

[sophister]

yeah, thanks!!
But now I have another question.

you see, when I show the table in the QTextEdit, the INTEGER cannot display appropriately.

I use the following code to display the int age---
age = query.value(3).toInt();

Where am I wrong??
Would you plz tell me??

[JhonJames]

mmm...

int age = query.value(3).toInt();
...
textEdit->append( QString("Age = %1").arg( age ) );

int age = query.value(3).toInt();
...
textEdit->append( QString("Age = %1").arg( age ) );

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That should work... If "age" is in column 3 of table and "age"'s type is Integer.

[sophister]

Thank you very much!!
But why the following codes don't work----
name = query.value(1).toString();
sex = query.value(2).toString();
age = query.value(3).toInt();
textEdit->append( name + '\t' + sex + '\t' +age);
Sorry to trouble you again.

[JhonJames]

QString name = query.value(1).toString();
QString sex = query.value(2).toString();
int age = query.value(3).toInt();
textEdit->append( QString("%1\t%2\t%3").arg( name ).arg( sex ).arg( age ) );
 
//or 
 
textEdit->append( name + "\t" + sex + "\t" + QString::number(age) );

QString name = query.value(1).toString();
QString sex = query.value(2).toString();
int age = query.value(3).toInt();
textEdit->append( QString("%1\t%2\t%3").arg( name ).arg( sex ).arg( age ) );

//or 

textEdit->append( name + "\t" + sex + "\t" + QString::number(age) );

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[sophister]

Thanks!!
I really learn a lor from you!!

[sophister]

Sorry to bother you again, I use the following codes to insert data into table, but I am sure there is something wrong with the following codes---
QSqlQuery insert(db);
insert.exec("select * from Person");
int num = insert.size();

How can I get the numbers of the records in this table??
QSqlQuery::size, or QSqlQuery::numberRowAffected(), do not work!!
They two return -1!!
Where is wrong??

[JhonJames]

Try with this:

QSqlQuery insert(db);
if (!insert.exec("select * from Person"))
  QMessageBox::critical(0, "Error", insert.lastError().text());
else
  QMessageBox::information(0, "Successfull", QString("Query successfully with %1 rows affected").arg( insert.numRowsAffected() ));

QSqlQuery insert(db);
if (!insert.exec("select * from Person"))
  QMessageBox::critical(0, "Error", insert.lastError().text());
else
  QMessageBox::information(0, "Successfull", QString("Query successfully with %1 rows affected").arg( insert.numRowsAffected() ));

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With this code you can see the error or the number of rows affected by query.

[talk2amulya]

try:

QSqlQuery query("SELECT * FROM Person", db);
int num = query.size();
textEdit->append("Number of persons: " + QString::number(num));

QSqlQuery query("SELECT * FROM Person", db);
int num = query.size();
textEdit->append("Number of persons: " + QString::number(num));

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