An insertion anomaly occurs when adding a new record requires unrelated data. It commonly appears in poorly designed tables that combine information belonging to different entities. section 3.3 section 1.3
A product without a customer
Imagine one table storing customers and products together. When adding a product that nobody has bought, the table still requires valid customer information. The conflicting requirements prevent the product from being added, creating an insertion anomaly. section 1.3
Reduce insertion anomalies by improving the table design:
- Minimize data redundancy and define appropriate data types, constraints, and relationships among entities. section 3.3
- Break tables apart when dependencies create design problems, then connect the resulting tables with a foreign key when appropriate. section 6.7
