Functionally Determined and 1NF

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SUMMARY

The discussion centers on the relationship between primary keys and First Normal Form (1NF) in relational databases. It establishes that if a relation R has a primary key (PK) but is not in 1NF, then PK does not functionally determine the table. Once R is normalized to 1NF, the original PK may no longer serve as the primary key. This conclusion is definitive and highlights the importance of normalization in database design.

PREREQUISITES
  • Understanding of relational database concepts
  • Familiarity with primary keys and their role in database tables
  • Knowledge of database normalization, specifically First Normal Form (1NF)
  • Experience with relational database management systems (RDBMS)
NEXT STEPS
  • Research the principles of database normalization, focusing on 1NF
  • Learn about functional dependencies in relational databases
  • Explore the implications of primary key changes after normalization
  • Study examples of tables transitioning from non-1NF to 1NF
USEFUL FOR

Database designers, data architects, and students of database management who seek to understand the implications of normalization on primary keys and functional dependencies.

WWGD
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Hi All,
Say we have a relation R ( i.e., a table in a relational DB ), which has a primary key PK, but R is not

in 1 NF. I guess we then conclude that PK _does not_ functionally-determine the table, since, after

the table is put in 1NF, PK is o longer the primary key, right? It seems obviously true, but I have

been wrong before...

Thanks.
 
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It might help to say that "1 NF" means First Normal Form.
 

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