- Support NULL database values (fixes #987 and #988)

  - check for NULL values on load
  - show "NULL" in attribute table and identify results
  - support entry of "NULL" in attribute table or dialog
- free result of PQexec in postgres provider (fixes memory leaks)


git-svn-id: http://svn.osgeo.org/qgis/trunk@8217 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: jef

src/app/qgsattributedialog.cpp

@@ -67,7 +67,11 @@ QgsAttributeDialog::~QgsAttributeDialog()
 
 QString QgsAttributeDialog::value(int row)
 {
-  return mTable->item(row,1)->text();
+  QString val = mTable->item(row,1)->text();
+  if(val=="NULL")
+    return QString::null; 
+  else
+    return mTable->item(row,1)->text();
 }
 
 bool QgsAttributeDialog::isDirty(int row)

src/app/qgsattributetable.cpp

@@ -461,7 +461,10 @@ bool QgsAttributeTable::commitChanges(QgsVectorLayer* layer)
             fieldIndex = provider->indexFromFieldName(record_it.key());
             if(fieldIndex != -1)
             {
-              newAttMap.insert(fieldIndex, record_it.value());
+              if( record_it.value()=="NULL" )
+                newAttMap.insert(fieldIndex, QVariant(QString::null) );
+              else
+                newAttMap.insert(fieldIndex, record_it.value());
             }
             else
             {
@@ -572,7 +575,7 @@ void QgsAttributeTable::putFeatureInTable(int row, QgsFeature& fet)
   for (it = attr.begin(); it != attr.end(); ++it)
   {
     // get the field values
-    setText(row, h++, it->toString());
+    setText(row, h++, it->isNull() ? "NULL" : it->toString());
   }
 }
 

src/app/qgsmaptoolidentify.cpp

@@ -303,7 +303,7 @@ void QgsMapToolIdentify::identifyVectorLayer(QgsVectorLayer* layer, const QgsPoi
 	      {
 		featureNode->setText(1, it->toString());
 	      }
-	    mResults->addAttribute(featureNode, fields[it.key()].name(), it->toString());
+	    mResults->addAttribute(featureNode, fields[it.key()].name(), it->isNull() ? "NULL" : it->toString());
 	  }
 
 	// Calculate derived attributes and insert: