Q3SqlForm Class Reference
[Qt3Support module]

Detailed Description

The Q3SqlForm class creates and manages data entry forms tied to SQL databases.

Typical use of a Q3SqlForm consists of the following steps:

• Create the widgets you want to appear in the form.
• Create a cursor and navigate to the record to be edited.
• Create the Q3SqlForm.
• Set the form's record buffer to the cursor's update buffer.
• Insert each widget and the field it is to edit into the form.
• Use readFields() to update the editor widgets with values from the database's fields.
• Display the form and let the user edit values etc.
• Use writeFields() to update the database's field values with the values in the editor widgets.

Note that a Q3SqlForm does not access the database directly, but most often via QSqlFields which are part of a Q3SqlCursor. A Q3SqlCursor::insert(), Q3SqlCursor::update() or Q3SqlCursor::del() call is needed to actually write values to the database.

Some sample code to initialize a form successfully:

 QLineEdit  myEditor(this);
 Q3SqlForm   myForm(this);
 Q3SqlCursor myCursor("mytable");

 // Execute a query to make the cursor valid
 myCursor.select();
 // Move the cursor to a valid record (the first record)
 myCursor.next();
 // Set the form's record pointer to the cursor's edit buffer (which
 // contains the current record's values)
 myForm.setRecord(myCursor.primeUpdate());

 // Insert a field into the form that uses myEditor to edit the
 // field 'somefield' in 'mytable'
 myForm.insert(&myEditor, "somefield");

 // Update myEditor with the value from the mapped database field
 myForm.readFields();
 ...
 // Let the user edit the form
 ...
 // Update the database
 myForm.writeFields();  // Update the cursor's edit buffer from the form
 myCursor.update();        // Update the database from the cursor's buffer

If you want to use custom editors for displaying and editing data fields, you must install a custom Q3SqlPropertyMap. The form uses this object to get or set the value of a widget.

See also installPropertyMap() and Q3SqlPropertyMap.

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