Decomposing a Table to Prevent Update Anomalies

Normalization is a design technique that removes duplicated data from a table to prevent update anomalies. When one table holds both customer names and their orders, the same customer name appears repeated across rows. Update just one of those rows, and the rows disagree — an update anomaly. Decomposing the table into a customers table and an orders table keeps the name in one place, so the data can never disagree.