The data type of the entity attribute defined in the CDM will be converted to the data type of the target database pair. Before CDM generates PDM, a DBMS must be selected as the target database. Only by converting CDM to PDM can the design work at this stage be completed. Note: The main content of LDM is between CDM and PDM.ĬDM completes the outline design of the information system, but in the physical design stage of the database, detailed background design must be carried out on this basis. (4) Click the "OK" button to start generating LDM. (3) Select the Selection tab, you can select CDM, entity, as shown in Figure 5-5. (2) Select the Detail tab to set other options. (1) Open the CDM model, select the Tools-Generate Logical Data Model command, and open the LDM Generation Options window as shown in Figure 5-4. The specific method for CDM to generate LDM is as follows: Although LDM is still independent of the DBMS, it can design objects such as foreign keys, indexes, and views. LDM is a new model of PowerDesigner 15, used to complete the logical design of the information system. (3) Establish entities and connections between entities. You can use the icons in the tool window to design the ER diagram in the design window. The working area includes the browser window on the left, the design window on the right, the output window on the lower side and the floating tool window (Palette). (2) Click the "OK" button to open the CDM workspace as shown in Figure 5-3. (1) Select the File-New Model command, and the window shown in Figure 5-2 will pop up. These issues will become the basis for establishing CDM. These include business-related entities, relationships between entities, and special business rules. The business process problem has been clarified in BPM, and the information that needs to be stored is extracted from it on this basis. Therefore, before creating business rules, you must first clarify the constraint relationship between the data. The system checks whether this information violates specific business rules. When the information contained in the entity changes,
#Conceptual data model powerdesigner software
A business rule can be an industry standard, a customer requirement or a software development specification manual.
The definition of domain is of great significance in model design, making it easier to standardize attributes in different entities.īusiness rules reflect the special data integrity constraints of the objects described by the information system. After the domain is defined, it can be shared and used by the attributes of multiple entities. According to the quantitative correspondence between entities, contacts can usually be divided into: one to one contact (One to One), one to many contact (One to Many), many to many contact (Many to Many), recursive contact (Recursive Relationship) and Identify Relationship (Identify Relationship), etc.ĭomain is the value range of one or some attributes. The relationship between entities and attributes is shown in Figure 5-1.Įntities can be related to each other through relationships. For example: a certain employee, name: Diaosi, gender: male, these indicators represent the attributes of this entity. It may be tangible or intangible, concrete or abstract, animate or inanimate.Įach entity has a set of characteristics, called entity attributes, used to describe the state and characteristics of the entity. At present, ER shows the most popular expression of CDM.Īn entity is an "object" that can be distinguished from other objects in the real world. Usually CDM uses Entity-Relation Graph (ER graph) to represent (the concept of "entity" and "relation").
Generate OOM (Object-Oritented MOdel, object-oriented model) class diagram.Converted to PDM (Physical Data Model, physical data model).
#Conceptual data model powerdesigner verification
Legal verification of data sheet design.The objects contained in the CDM are usually not implemented in the physical database. Conceptual Data Model (CDM): expresses the overall logical structure of data, which is independent of any software and data storage structure, that is, it is only the mutual understanding between system analysts, application designers, maintenance personnel and users The common language does not target specific database platforms (such as Oracle or SQL Server) and tools (PowerBuilder).
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