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Normalization: Designing a Database That Won't Break

Three practical guidelines — one table, one subject; no repeating groups of fields; every fact in exactly one place — capture nearly all of the everyday benefit of formal normalization.

Field Notes: Three Guidelines, Not a Formula

Normalization is simply the formal name for organizing tables well. You don't need to memorize its formal rules — often called First, Second, and Third Normal Form in textbooks — to build a solid database, but three practical guidelines capture nearly all of the everyday benefit:

- Every table should describe exactly one kind of thing. If a table's name would need the word "and" to accurately describe what it holds — "CustomersAndOrders" — it should probably be split into two tables. - Avoid repeating groups of similar fields, like Product1, Product2, Product3, within a single Orders row. This almost always signals a missing related table is needed instead. - Every piece of information should be stored in exactly one place. If a customer's address needs to be typed into more than one table, it's a sign that a relationship, rather than duplicated data, should be connecting those tables instead.

More lessons in Microsoft Access · Next: What Is a Query? · Previous: Building Relationships and Enforcing Referential Integrity

Field Notes: Three Guidelines, Not a Formula

Normalization is simply the formal name for organizing tables well. You don't need to memorize its formal rules — often called First, Second, and Third Normal Form in textbooks — to build a solid database, but three practical guidelines capture nearly all of the everyday benefit:

- Every table should describe exactly one kind of thing. If a table's name would need the word "and" to accurately describe what it holds — "CustomersAndOrders" — it should probably be split into two tables. - Avoid repeating groups of similar fields, like Product1, Product2, Product3, within a single Orders row. This almost always signals a missing related table is needed instead. - Every piece of information should be stored in exactly one place. If a customer's address needs to be typed into more than one table, it's a sign that a relationship, rather than duplicated data, should be connecting those tables instead.