Chapter 2 Introducing PowerDesigner
Once the data structure is well defined, Database Administrators can optimize, denormalize, and create the database. You will use a Physical Data Model (PDM), which is a representation of a real database and associated objects running on a server with complete information on the structure of the physical objects, such as tables, columns, references, triggers, stored procedures, views, and indexes.
A PowerDesigner PDM can be used to generate all of the database code for any of the 50 supported RDBMSs. The PDM can be created by reverse engineering from a script or from a live server through a standard ODBC connection. By maintaining a PDM and a CDM, you can ensure that your final implementation exactly matches your system requirements, and that your analysis and design efforts are reflected exactly in your actual systems.
You may also use a Logical Data Model (LDM), which is a special RDBMS-independent version of a PowerDesigner PDM, and which can be used as a bridge between a CDM and a regular deployable PDM. More technically precise than a CDM, an LDM allows you to resolve many-to-many and super/sub-type relationships, de-normalize your data structures, and define indexes, without specifying a particular RDBMS.
If you are responsible for database replication, you will also use an Information Liquidity Model (ILM), which provides a global representation of the replication of information from a source database to one or several remote databases.
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