Im New in Qt
I have problem in my app.
This is my code:
voidDialog::on_tableView_activated(constQModelIndex&index)
{
QString valu=ui->tableView->model()->data(index).toString();
QSqlQuery qryview;
qryview.prepare("SELECT* FROM employ where nomper='"+valu+"' or prenomper='"+valu+"'");
ui->lineEdit_2->setText(qryview.value(0).toString());
ui->lineEdit_3->setText(qryview.value(1).toString());
}
I want to recuperate my data in QLineEdit.
When I use SQLite, there is no problem.
But when I use MySQL no result shows in lineEdit.
qsqlquery::value: not positioned on a valid record.
The problem is that you are trying to retrieve the row without initializing it. The right way to do this is by using query.next(), below is the code example:
QString valu=ui->tableView->model()->data(index).toString();
QSqlQuery qryview;
qryview.prepare("SELECT* FROM employ where nomper='"+valu+"' or prenomper='"+valu+"'");
qryview.exec();
while(qryview.next()) {
ui->lineEdit_2->setText(qryview.value(0).toString());
ui->lineEdit_3->setText(qryview.value(1).toString());
}
This should work, if not try to print the lastQueryError and see if query is executed coreectly.
Related
I'm trying to save the username from the database into a variable to use in another QDialog, but the variable is blank when I try to use it in the other dialog
qry.prepare("select nome from Users where email='"+user+"' and senha='"+password+"'");
if(qry.exec()) {
int count=0;
while(qry.next()) {
ui->label_2->setText(qry.value(0).toString());
count++;
}
if (count == 1) {
usuario = ui->label_2->text();
ui->errologin->setText("");
logado= true;
this->hide();
}
This is how i'm trying to call it in the other Dialog:
ui->label->setText(log.usuario);
And this ist the variable declaration in the header file:
public:
explicit login(QWidget *parent = nullptr);
~login();
bool logado;
QString usuario;
There is one thing that you could do better, instead of this:
qry.prepare("select nome from Users where email='"+user+"' and senha='"+password+"'");
Replace it by:
qry.prepare("select nome from users where email=? and senha=?");
qry.bindValue(0, user);
qry.bindValue(1, password);
Please, don't build your queries concatenating strings.
Other than that, there is no way to tell where is your mistake, because you don't provide a minimal reproducible example, as #AlanBirtles and #eyllanesc have requested. I don't see the problem in the code you provided, it may be somewhere hidden in the code that you don't show.
Another advice: trying to reduce your problem to a minimal test program may help you to find the problem by yourself. For instance, if you doubt about your usage of the QSqlQuery class, then put your query in a console program and see if it returns the correct results. If it still doesn't work right, then post your (full) test program here in SO.
Using C++ Qt framework and sql server 2008 I've been trying to insert a record into a table with an identity field and retrieve the identity value. Below is a simplified code sample which actually does do the insert but just doesn't retreive the identity. The identity returned from query.value(0) is an invalid QVariant.
QSqlQuery query(*pConn);
query.prepare("insert into [VH_MANUFACTURER] values ('sRRS test man code','RRS type','RRS logo file',1,'RRS SEO para','RRS description','RS');"
"select SCOPE_IDENTITY();");
if(query.exec())
{
if(query.next())
{
QVariant identity = query.value(0);
int id=identity.toInt();
}
}
I've tried using select ##identity instead of scope_identity with no improvement and also QSqlQuery .lastInsertId() which also returns an invalid QVariant, see below.
bool bFeature = pConn->driver()->hasFeature(QSqlDriver::LastInsertId);
QSqlQuery query(*pConn);
query.prepare("insert into [VH_MANUFACTURER] ([MFG_NAME],[MFG_TYPE],[MFG_LOGO],[MFG_ACTIVE],[MFG_SEO_CONTENT],[MFG_DESCRI],[MFG_CAPMANCODE]) values ('sRRS test man code','RRS type','RRS logo file',1,'RRS SEO para','RRS description','RS')");
if(query.exec())
{
QVariant id=query.lastInsertId();
}
hasFeature returns true, so the driver is supposed to support what I'm trying to do.
Just to test the sql , I ran the sql directly through Sql Server Management Studio and it inserts as expected and returns the identity value correctly.
Finally found a work around using OUTPUT clause in sql. I don't exactly know why the other methods I tried don't work. There is a sql server bug associated with this feature but that doesn't explain why it worked in ssms but not in c++ Qt code. The sample below show's the work around. Here's the reference I used to solve this.
bool bFeature = pConn->driver()->hasFeature(QSqlDriver::LastInsertId);
QSqlQuery query(*pConn);
query.prepare("insert into [VH_MANUFACTURER] ([MFG_NAME],[MFG_TYPE],[MFG_LOGO],[MFG_ACTIVE],[MFG_SEO_CONTENT],[MFG_DESCRI],[MFG_CAPMANCODE]) OUTPUT INSERTED.MFG_ID values ('sRRS test man code','RRS type','RRS logo file',1,'RRS SEO para','RRS description','RS')");
if(query.exec())
{
if(query.next())
{
QVariant id=query.value("MFG_ID");
}
}
When you try to close Swing application and you change same value in field, application ask you if you want to save changes.
My first question is why RAP application doesn't ask same question ?
Second and more important question is how to force validation of fields change and how to manipulate this.
for example :
I have table with rows and some fields below table. If I click on row some value is entered in fields. I can change this value and click button save.
I would like to force change validation on row click. So if changes ware applied and if I click on row, application should warn me that some changes are not saved.
But I should be able to manipulate what is change and what is not. For example if table on row click fill some data if fields this is not change, but if I entered value is same fields this is change.
I discovered method
checkSaveNeeded();
But it does nothing. (if I change values or not)
I see that every field has mathod
#Override
public final void checkSaveNeeded() {
if (isInitialized()) {
try {
propertySupport.setPropertyBool(PROP_SAVE_NEEDED, m_touched || execIsSaveNeeded());
}
catch (ProcessingException e) {
SERVICES.getService(IExceptionHandlerService.class).handleException(e);
}
}
}
so I should manipulate changes throw m_touched ?
How is this handled in Scout ?
ADD
I am looking for function that check for dirty fields and pops up message dialog, same as when closing form, and way to set fields dirty or not.
I look here and here, but all it describes is how values is stored for popup messages and dot how to fire this messages (validation).
My first question is why RAP application doesn't ask same question ?
I am not sure to know which message box you mean but it should be the case.
There are several questions about unsaved changes and form lifecycle in the Eclipse Scout Forum. I think you can find them with Google.
I have also taken the time to start to document it in the Eclipse Wiki:
Scout Field > Contribution to unsaved changes
Form lifecycle
I think you should implement execIsSaveNeeded() in the corresponding field. The default implementation in AbstractTableField uses the state of the rows, but you can imagine the logic you want.
#Order(10.0)
public class MyTableField extends AbstractTableField<MyTableField.Table> {
#Override
protected boolean execIsSaveNeeded() throws ProcessingException {
boolean result;
//some logic that computes if the table field contains modification (result = true) or not (result = false)
return result;
}
//...
I hope this helps.
I am looking for function that check for dirty fields and pops up message dialog, same as when closing form.
Are you speaking from this message box that appears when the user clicks on Cancel in the form?
There is no specific function that you can call for that. But you can check the beginning of the AbstractForm.doCancel() function. It is exactly what you are looking for.
I have rewritten it like this:
// ensure all fields have the right save-needed-state
checkSaveNeeded();
// find any fields that needs save
AbstractCollectingFieldVisitor<IFormField> collector = new AbstractCollectingFieldVisitor<IFormField>() {
#Override
public boolean visitField(IFormField field, int level, int fieldIndex) {
if (field instanceof IValueField && field.isSaveNeeded()) {
collect(field);
}
return true;
}
};
SomeTestForm.this.visitFields(collector);
MessageBox.showOkMessage("DEBUG", "You have " + collector.getCollectionCount() + " fields containing a change in your form", null);
I have changed the Visitor to collect all value fields with unchanged changes. But you can stick to the original visitField(..) implementation. You cannot use P_AbstractCollectingFieldVisitor because it is private, but you can have a similar field visitor somewhere else.
I am looking for a way to set fields dirty or not.
As I told you: execIsSaveNeeded() in each field for some custom logic. You can also call touch() / markSaved() on a field to indicate that it contains modifications or not. But unless you cannot do otherwise, I do not think that this is the correct approach for you.
I have recently begun working with QT and I'm having a small issue. I cant seem to understand how QVariant works. I've been going through the help and looking online but it is just not sinking in. In my project i am trying to populate a combo box with a list of manufacturers from a database. I have opened the database and pulled out the entries but I rename them all manValue. Now I understand why this is happening, the problem is I do not understand how to properly use QVariant to get the result I want. Originally i thought "manValue" was going to be the identifier for the string that held the actual value from the database but instead it reads the value from the database and makes sure it is not null, and then renames it. I already tried making a string before I assign the QVariant with any properties and assigning it the text i received from the database, and then inserting that string where manValue is but still no luck. Any help would be greatly appreciated. Sorry, I know this is going to be simple I'm just a noob and the help docs often confuse me.
QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
db.setHostName("LOCALHOST\\TestERPServer");
db.setDatabaseName("TestERPConnection");
if (db.open())
{
QMessageBox::information(this,"Connected","Connection to the Database was Established\n"
"\nStatus: Connected");
QSqlQuery mfrQry;
if (mfrQry.exec("SELECT * FROM erp_data.manufacturers;"))
{
if (mfrQry.value(1) == "")
{
QMessageBox::information(this,"No Connection","Nothing in the Manufacturer Database\n"
"\nError: " + db.lastError().text());
}
else
{
while (mfrQry.next())
{
ui->mfrComboBox->addItem("manValue",QVariant(mfrQry.value(1)));
}
}
}
else
{
QMessageBox::information(this,"No Connection","Connection to the Manufacturer Database could not be Established\n"
"\nError: " + db.lastError().text());
}
}
else
{
QMessageBox::information(this,"No Connection","Connection to the Database could not be Established\n"
"\nError: " + db.lastError().text());
}
The first problem in the provided code has to do with the way you manipulate the QSqlQuery.
Successfully executed SQL statements set the query's state to active
so that isActive() returns true. Otherwise the query's state is set to
inactive. In either case, when executing a new SQL statement, the
query is positioned on an invalid record. An active query must be
navigated to a valid record before values can be retrieved.
In order to move to a valid record you have to use one of the following:
next()
previous()
first()
last()
seek()
Once you are on a valid record you have to use the value() function in order to take the column you want. The returned value is QVariant so you need to convert to the desired type using one of the many toSomething functions QVariant provides.
So in your case the code should look like this:
QSqlQuery mfrQry;
if (mfrQry.exec("SELECT * FROM erp_data.manufacturers;"))
{
// This will loop through all records returned by the query
while (mfrQry.next()) {
// mfrQry.value(COLID) returns a QVariant containing the data of the current
// record in column COLID.
// Using toString we convert it to String
QString stringValue = mfrQry.value(COLID).toString();
// Now handle the QString the way you want...
}
}
my question is basically the same as #Bob Black's Cannot access sitecore item field via API but I agree with #techphoria414 that the accepted solution is not necessary and in my case does not work.
In my own words, I have a template Departure that I have been using for about a year now creating and updating items programmatically. I have added a new field Ship to the template. When I create a new item the field comes up as null when I try to access it using departure.Fields["Ship"]. If I step over the line causing the exception then after calling departure.Editing.EndEdit() I can then see the Ship field if I call departure.Fields.ToList(). If I add the template to a content item via the Sitecore GUI I can see the field and use it, and if I look at a content item which is based on the template I can see the new field too. So it is only when I access the template/item programmatically that it is null.
I have sitecore running on my local machine with a local sqlserver, and publish to my local machine.
Here is my code
String ship = "MSDisaster";
foreach (Language language in SiteLanguages)
{
departure = departure.Database.GetItem(departure.ID, language);
departure.Editing.BeginEdit();
try
{
departure.Fields["StartDate"].Value = GetSitecoreDateString(xDep, "StartDate");
departure.Fields["EndDate"].Value = GetSitecoreDateString(xDep, "EndDate");
departure.Fields["Guaranteed"].Value = xDep.SelectSingleNode("./Guaranteed").InnerText;
departure.Fields["Status"].Value = xDep.SelectSingleNode("./Status").InnerText;
departure.Fields["Currency"].Value = ConvertLanguageToCurrency(language);
departure.Fields["Market"].Value = ConvertLanguageToMarket(language);
departure.Fields["TwinSharePrice"].Value = GetPrice(xDep, "twn", language);
departure.Fields["SinglePrice"].Value = GetPrice(xDep, "sgl", language);
if (!String.IsNullOrEmpty(ship))
departures.Fields["Ship"].Value = ship;
}
catch (Exception ex)
{
departure.Editing.CancelEdit();
log.Error(ex);
throw ex;
}
departure.Editing.EndEdit();
}
So, how do I get the field be picked up?
Thanks,
James.
Firstly do you see the field in the web database in the sitecore administration.
If you do the item has the fields, you then should check the template assigned on the item and double check that the field is actually called "ship" and check the case as ive seen this as an issue before.
Also check the security on the item and field just in case anyone changed anything.
Next try and get the data from the item but instead of using the field name, use the field ID.
Let me know how you go?
Chris
Sorry Chris, StackOverflow, and the others who looked at my questions. It was a stupid typo. It's even there in my question
departure.Fields["SinglePrice"].Value = GetPrice(xDep, "sgl", language);
if (!String.IsNullOrEmpty(ship))
departures.Fields["Ship"].Value = ship;
}
departure is the item I am working on, departures is the collection it belongs to... doh.
So what is the protocol here? Do I delete my question now because it isn't really going to help anyone code better?
James.