In database application developments, data coexists in memory and disk spaces. To manipulate the memory data, the general programing languages are used and to manipulate the disk data, SQL is used. In particular, the procedural languages for the memory manipulation are difficult to create and manage than declarative languages such as SQL. Thus, this paper shows that a particular structure of memory data, tree structured, can be manipulated by SQL. Most of all, the model data of the user interfaces can be represented by a tree structure and thus, it can be processed by SQL except non set computations. The non set computations could be done by helper classes. The SQL memory data manipulation is more suited to the database application developments which have few complex computations.