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Databases & SQL vocabulary · Data Modeling and Normalization

Normal form

Meaning in databases & SQL, with examples

nounCommon term

In databases & SQL, normal form means: One of a series of rules for table design (1NF, 2NF, 3NF and higher); each level removes a particular kind of repeated or badly placed data.

In Turkish: normal form, normal biçim

How it is used

In short: 1NF means one value per cell and no repeating groups; 2NF removes columns that depend on only part of a composite key; 3NF removes columns that depend on other non-key columns. Most business schemas aim for third normal form.

Example sentences

  1. Storing three phone numbers in one column breaks first normal form.

  2. The schema is in third normal form except for the reporting tables.

Common collocations

  • first normal form
  • third normal form
  • 1NF
  • 3NF
  • Boyce-Codd normal form
  • normalizationThe process of organizing tables so that each fact is stored in only one place, which reduces repeated data and prevents update mistakes.
  • denormalizationDeliberately storing some data in more than one place, or combining tables, to make reads faster, while accepting more work to keep the copies correct.
  • composite keyA key made of two or more columns that identify a row only when used together, such as order ID plus product ID in an order items table.
  • ER diagramA drawing of a database design that shows the entities (usually tables), their attributes and the relationships between them, such as one-to-many.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Data Modeling and Normalization

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