20 encounters of the information kind: data normalization – third normal form or performance and usage

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I am not a purist when it comes to data modeling (logical and physical). This may be one of my flaws (there are so few - haha). I do believe that logical modeling and physical modeling are two different arts with two different skill sets.

Logical modeling requires a person to understand and depict the business rules in a modeling tool, using things such as super/subtype relationships, etc. Logical data modeling represents the organization data. Definitions of entities and attributes are a must for any good logical data model, as well an understanding of how business is conducted. I have seen some of the best logical data modelers who have never seen a database or the DDL (data definition language) that creates the database objects.

Physical modeling takes into account how the data is inserted, updated or deleted - as well as how the data is used (performance and usage). Tuning of the insert, update or delete and the queries is a must, and sometimes we get pretty creative on when (or when not) to build indexes. I call this an "indexing strategy." Every data group needs one for each database you are designing. I have seen some of the best physical data modelers and database designers who have never seen a data modeling tool.

When you are lucky enough to have both in one person – hold on to them!

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About Author

Joyce Norris-Montanari

President of DBTech Solutions, Inc

Joyce Norris-Montanari, CBIP-CDMP, is president of DBTech Solutions, Inc. Joyce advises clients on all aspects of architectural integration, business intelligence and data management. Joyce advises clients about technology, including tools like ETL, profiling, database, quality and metadata. Joyce speaks frequently at data warehouse conferences and is a contributor to several trade publications. She co-authored Data Warehousing and E-Business (Wiley & Sons) with William H. Inmon and others. Joyce has managed and implemented data integrations, data warehouses and operational data stores in industries like education, pharmaceutical, restaurants, telecommunications, government, health care, financial, oil and gas, insurance, research and development and retail. She can be reached at jmontanari@earthlink.net.

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