Q3SqlPropertyMap Class Reference
[Qt3Support module]

Detailed Description

The Q3SqlPropertyMap class is used to map widgets to SQL fields.

The SQL module uses Qt object properties to insert and extract values from editor widgets.

This class is used to map editors to SQL fields. This works by associating SQL editor class names to the properties used to insert and extract values to/from the editor.

For example, a QLineEdit can be used to edit text strings and other data types in Q3DataTables or Q3SqlForms. Several properties are defined in QLineEdit, but only the text property is used to insert and extract text from a QLineEdit. Both Q3DataTable and Q3SqlForm use the global Q3SqlPropertyMap for inserting and extracting values to and from an editor widget. The global property map defines several common widgets and properties that are suitable for many applications. You can add and remove widget properties to suit your specific needs.

If you want to use custom editors with your Q3DataTable or Q3SqlForm, you must install your own Q3SqlPropertyMap for that table or form. Example:

 Q3SqlPropertyMap *myMap  = new Q3SqlPropertyMap();
 Q3SqlForm        *myForm = new Q3SqlForm(this);
 MyEditor myEditor(this);

 // Set the Q3SqlForm's record buffer to the update buffer of
 // a pre-existing Q3SqlCursor called 'cur'.
 myForm->setRecord(cur->primeUpdate());

 // Install the customized map
 myMap->insert("MyEditor", "content");
 myForm->installPropertyMap(myMap); // myForm now owns myMap
 ...
 // Insert a field into the form that uses a myEditor to edit the
 // field 'somefield'
 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 fields with the values in the form
 myForm->writeFields();
 ...

You can also replace the global Q3SqlPropertyMap that is used by default. (Bear in mind that Q3SqlPropertyMap takes ownership of the new default map.)

 Q3SqlPropertyMap *myMap = new Q3SqlPropertyMap;

 myMap->insert("MyEditor", "content");
 Q3SqlPropertyMap::installDefaultMap(myMap);
 ...

See also Q3DataTable, Q3SqlForm, and Q3SqlEditorFactory.

Member Function Documentation

Q3SqlPropertyMap::Q3SqlPropertyMap ()

Constructs a Q3SqlPropertyMap.

The default property mappings used by Qt widgets are:

Q3SqlPropertyMap::~Q3SqlPropertyMap ()   [virtual]

Destroys the Q3SqlPropertyMap.

Note that if the Q3SqlPropertyMap is installed with installPropertyMap() the object it was installed into, e.g. the Q3SqlForm, takes ownership and will delete the Q3SqlPropertyMap when necessary.

Q3SqlPropertyMap * Q3SqlPropertyMap::defaultMap ()   [static]

Returns the application global Q3SqlPropertyMap.

void Q3SqlPropertyMap::insert ( const QString & classname, const QString & property )

Insert a new classname/property pair, which is used for custom SQL field editors. There must be a Q_PROPERTY() clause in the classname class declaration for the property.

void Q3SqlPropertyMap::installDefaultMap ( Q3SqlPropertyMap * map )   [static]

Replaces the global default property map with map. All Q3DataTable and Q3SqlForm instantiations will use this new map for inserting and extracting values to and from editors. Q3SqlPropertyMap takes ownership of map, and destroys it when it is no longer needed.

QVariant Q3SqlPropertyMap::property ( QWidget * widget )

Returns the mapped property of widget as a QVariant.

See also setProperty().

void Q3SqlPropertyMap::remove ( const QString & classname )

Removes classname from the map.

void Q3SqlPropertyMap::setProperty ( QWidget * widget, const QVariant & value )   [virtual]

Sets the property of widget to value.

See also property().