DbStructureModel: Enable dragging of DB objects

Allow dragging (as in Drag & Drop) of database objects like tables and
views into other applications by sending the SQL code used to create
them.

src/DbStructureModel.cpp

@@ -1,6 +1,7 @@
 #include "DbStructureModel.h"
 #include "sqlitedb.h"
 #include <QTreeWidgetItem>
+#include <QMimeData>
 
 DbStructureModel::DbStructureModel(QObject* parent)
     : QAbstractItemModel(parent)
@@ -43,7 +44,15 @@ Qt::ItemFlags DbStructureModel::flags(const QModelIndex &index) const
     if(!index.isValid())
         return 0;
 
-    return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
+    // All items are enabled and selectable
+    Qt::ItemFlags flags = Qt::ItemIsEnabled | Qt::ItemIsSelectable;
+
+    // Only enable dragging for entire table objects
+    QString type = data(index.sibling(index.row(), 1), Qt::DisplayRole).toString();
+    if(type == "table" || type == "view" || type == "index" || type == "trigger")
+            flags |= Qt::ItemIsDragEnabled;
+
+    return flags;
 }
 
 QVariant DbStructureModel::headerData(int section, Qt::Orientation orientation, int role) const
@@ -153,3 +162,27 @@ void DbStructureModel::reloadData(DBBrowserDB* db)
     // Refresh the view
     reset();
 }
+
+QStringList DbStructureModel::mimeTypes() const
+{
+    QStringList types;
+    types << "text/plain";
+    return types;
+}
+
+QMimeData* DbStructureModel::mimeData(const QModelIndexList& indices) const
+{
+    // Loop through selected indices
+    QByteArray d;
+    foreach(QModelIndex index, indices)
+    {
+        // Only export data for valid indices and only for the SQL column, i.e. only once per row
+        if(index.isValid() && index.column() == 3)
+            d = d.append(data(index, Qt::DisplayRole).toString() + ";\n");
+    }
+
+    // Create the MIME data object
+    QMimeData* mime = new QMimeData();
+    mime->setData("text/plain", d);
+    return mime;
+}

src/DbStructureModel.h

@@ -23,6 +23,9 @@ public:
     int rowCount(const QModelIndex& parent = QModelIndex()) const;
     int columnCount(const QModelIndex& = QModelIndex()) const;
 
+    QStringList mimeTypes() const;
+    QMimeData* mimeData(const QModelIndexList& indices) const;
+
 private:
     QTreeWidgetItem* rootItem;
 };

src/MainWindow.ui

@@ -44,6 +44,12 @@
        <property name="contextMenuPolicy">
         <enum>Qt::CustomContextMenu</enum>
        </property>
+       <property name="dragEnabled">
+        <bool>true</bool>
+       </property>
+       <property name="dragDropMode">
+        <enum>QAbstractItemView::DragOnly</enum>
+       </property>
        <property name="alternatingRowColors">
         <bool>true</bool>
        </property>
@@ -266,7 +272,7 @@
          <rect>
           <x>0</x>
           <y>0</y>
-          <width>278</width>
+          <width>763</width>
           <height>444</height>
          </rect>
         </property>