Summary
Through various examples in this chapter, we saw how the process of normalization organizes a database in a way that reduces redundancy and dependency within its tables.
Dependency and redundancy in database tables increase the likelihood of data anomalies, which come in many forms. Update anomalies occur due to redundancy, which makes it possible to update some, but not all, of the associated records. Physical (as opposed to logical) dependencies are the root cause of insertion and deletion anomalies. When too many details of varying granularity are bunched into a single table, inserting or deleting records that do not match all the criteria becomes difficult. The domain anomaly is the hardest to spot because it requires functional knowledge of the data in question.
Database normalization can be applied through escalating stages of formal rules called normal forms, ranging from 1NF to 6NF to avoid such anomalies. The most commonly used normal forms are the first through...
