Progress of SQL "select"

Is there any nice way of receiving info about progress of "select" statement in qt?
First step looks clear: select count().... and use it as 100%. But what's next? Determining size of one record? Very dirty way...

What would you need the record's size for? SELECT COUNT() and QSqlQuery::size() return the number of records --- each of them counts as 1.

Just remember that if you want to display that progress, you have to let Qt process events from time to time.

The question is: which events Qt should process from time to time?

Just invoke QCoreApplication::processEvents() with default parameter or with QEventLoop::ExcludeUserInputEvents.

Sorry, I can't understand your idea. Select() function is synchronous, it doesn't return until all data would be fetched. So where from should I call processEvents()?

Can you give some piece of example code?

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Originally Posted by brokensword

Select() function is synchronous, it doesn't return until all data would be fetched.

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I see we don't understand each other. Please define "progress of select statement".

I have a QSqlTableModel. I fill it with data using setFilter() or select() methods of QSqlTableModel. Both are synchronous (they don't return until all records would be fetched). Operation can take more then 5 minutes.

Everything I need to know is just how much records were fetched so far.

I've tried to make static QSqlTableModel object, fill it with data in separate thread and call rowsCount() (query->size()) in loop in main thread. It doesn't helps - rowsCount() (and query->size)) return 0 until model would be fully filled.

So is there any way to get QSqlTableModel filling progress info?

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Originally Posted by brokensword

Everything I need to know is just how much records were fetched so far.

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I see, I thought you were using QSqlQuery.

You might try connecting to QAbstractItemModel::rowsInserted() signal.

Didn't work. rowsInserted() signal is emmited only once - at the end of filling process.

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Originally Posted by jacek

I see, I thought you were using QSqlQuery.

You might try connecting to QAbstractItemModel::rowsInserted() signal.

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Quote:

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Originally Posted by brokensword

Didn't work. rowsInserted() signal is emmited only once - at the end of filling process.

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Too bad. I've checked the sources and it looks like QSqlTableModel (QSqlQueryModel actually) doesn't fetch the data row-by-row, but rather retrieves particular cells as needed in data() using QSqlQuery::seek().

Maybe you could create your own model that will load data using typical while( query.next() ) loop?