fix: a few compiler warnings

Author: ansgarbecker

source/dbconnection.pas

@@ -188,7 +188,7 @@   TDBObject = class(TPersistent)
 
       NodeType, GroupType: TListNodeType;
       constructor Create(OwnerConnection: TDBConnection);
-      destructor Destroy;
+      destructor Destroy; override;
       procedure Assign(Source: TPersistent); override;
       procedure UnloadDetails;
       procedure Drop;

source/dbstructures.interbase.pas

@@ -236,8 +236,9 @@ function TInterbaseProvider.GetSql(AId: TQueryId): string;
       '   RDB$CHARACTER_SET_ID'+
       ' FROM RDB$COLLATIONS';
     qGetCharsets: Result := 'SELECT RDB$CHARACTER_SET_NAME AS "Charset", RDB$CHARACTER_SET_NAME AS "Description" FROM RDB$CHARACTER_SETS';
+    else Result := inherited;
   end;
 end;
 
 
-end.
+end.

source/main.pas

@@ -7331,9 +7331,6 @@ procedure TMainForm.SynMemoQueryShowHint(Sender: TObject; HintInfo: PHintInfo);
   Obj: TDBObject;
   i, ColumnNameChars: Integer;
   Column: TTableColumn;
-  Parameters: TRoutineParamList;
-  Params: TStringList;
-  Param: TRoutineParam;
 begin
   // Activate hint for SQL function in query editors
   Edit := Sender as TSynEdit;
@@ -7797,8 +7794,6 @@ procedure TMainForm.SynMemoQueryDragDrop(Sender, Source: TObject; X,
 procedure TMainForm.FormDropFiles(Sender: TObject;
   const FileNames: array of string);
 var
-  i: Integer;
-  Tab: TQueryTab;
   Files: TStringList;
 begin
   // One or more files from explorer or somewhere else was dropped onto the

source/table_editor.pas

@@ -1855,6 +1855,7 @@ procedure TfrmTableEditor.listColumnsCreateEditor(Sender: TBaseVirtualTree;
   // Start cell editor
   VT := Sender as TLazVirtualStringTree;
   Col := Sender.GetNodeData(Node);
+  EditLink := nil;
   case Column of
     ColNumDatatype: begin // Datatype pulldown
       DatatypeEditor := TDatatypeEditorLink.Create(VT, True, Col^);