Design DataBase (DDB)
The following figures show the hierarchical structure of the
Bartels AutoEngineer object oriented Design DataBase (DDB). All design objects are stored in a single file, and each design object belongs to a certain class (e.g., drawing, symbol, etc.) and can inherit (include) symbols from the same or from other classes depending on the design context. Database and design objects can be manipulated independently from other objects and may be copied, extracted, included or deleted as required. The database knows about the design relations, i.e., copying a schematic sheet automatically copies inherited part and pin symbols. All database files, design or library, have the same file format. Whether a file is a design or a library file depends on its (contextual) content rather than on its file structure.
Figure 1 explains the schematic capture graphical object relations:
Figure 1: SCM Database Hierarchy
Figure 2 shows the relations between the logical and physical parts as well as an example for pin/gate/group swap information and power supply pins. This description can also be used to specify a fully hierarchical design, e.g., for ASICs or custom ICs:
Figure 2: Part Data Sheet with Loglib Definition
Figure 3 illustrates the construction of a printed circuit board. Arbitrarily shaped polygons can be created in any design hierarchy level. A polygon may also contain arcs, which are handled by the system as basic element types, i.e., all arc calculations are precise without using arc interpolation:
Figure 3: Layout Database Hierarchy
Figure 4 explains the overall dataflow within the complete design system including schematic capture and PCB design. Consider the central position of the
Job File which, at the end of the design process, contains all design-specific objects such as the schematic sheets, the PCB layout, the netlist data, and the job-specific library data:
Figure 4: Bartels AutoEngineer System Flow Diagram
Please note that the same design file which contains all SCM and PCB data may also contain part lists or other table-oriented information. The
Bartels AutoEngineer database software includes an SQL engine which is able to bundle SQL table information transparently into its own object class and automatically build indices for quick database access. SQL database access optimization works with multiple tables, too. All database queries, whether to objects or via the SQL engine, are processed by a powerful variable key-length B-TREE algorithm. It is not necessary to copy symbol and/or part libarary data directly onto a schematic plan and/or a PCB layout, the schematic plan and the PCB layout objects only store (placement data) references to the placed symbols and/or parts. Library symbols and parts are copied into the design file when they are requested for placement for the first time. This automatically creates design-specific symbol and part libraries within the design file and leaves the designer with the opportunity to modify design-specific library elements without changing the original (master) library. The backup of a design is also much simplified, since a single DDB file ends up containing the complete SCM and PCB design and library data.