Architecting and designing
  
Leveling Data
Use this dialog box to specify options for creating a leveled data flow diagram. Depending on the complexity of the lines and symbols that are attached to the parent, you might not want to include the symbols that are attached to the lines.
The child diagram can contain 5 to 9 process symbols, and the data flows and data stores that support those processes. Data stores that are integral to the child diagram should be drawn completely within the parent symbol bitmap; those integral to the system as a whole should be drawn outside the parent symbol. Input data flows that are attached to the parent symbol start in a space outside the parent symbol bitmap, but must end inside the bitmap that is attached to a process or data store. Similarly, output data flows must start in a data store or process within the parent bitmap and end in a space outside. To achieve balance, all the data going into the parent symbol must go into the child diagram; all the data coming out of the parent symbol must come out of the child diagram.