![]() ![]() Data Duplication and Modification Anomalies Having the table serve many purposes introduces many of the challenges namely, data duplication, data update issues, and increased effort to query data. In general I like to see tables that have one purpose. Associating a salesperson with an sales officeĪs a DBA this raises a red flag.Listing the sales offices and phone numbers.Identifying the organization’s salespeople.The first thing to notice is this table serves many purposes including: Consider the following table: Note: The primary key columns are underlined I think once you understand the issues, you better appreciate normalization. The first is to minimize duplicate data, the second is to minimize or avoid data modification issues, and the third is to simplify queries.Īs we go through the various states of normalization we’ll discuss how each form addresses these issues, but to start, let’s look at some data which hasn’t been normalized and discuss some potential pitfalls. There are three main reasons to normalize a database. Conclusion – Can Database Normalization Get out of Hand?.Third Normal Form (3NF) Database Normalization.Second Normal Form (2NF) Database Normalization.First Normal Form (1NF) Database Normalization.Data Duplication and Modification Anomalies. ![]() Before we move on be sure you understand the definition of a database table. The progression from unruly to optimized passes through several normal forms: first, second, and third normal form.Īs tables satisfy each successive database normalization form, they become less prone to database modification anomalies and more focused toward a sole purpose or topic. As you apply these rules, new tables are formed. To achieve these objectives, we’ll use some established rules. This eliminates some issues stemming from database modifications.
0 Comments
Leave a Reply. |