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Theory

Basics

• database models
• Codd's 12 rules
• keys
• relationships
• dependencies
• ERD diagrams
• transactions

Normalization

• 1st normal form
• 2nd normal form
• 3rd normal form
• Boyce-Codd normal form

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you are at >> normalization >>1st normal form

1st normal form

Relation is in the 1NF, if the attributes are elementary or atomic. The table in this form may not contain repeating groups of information. Each column is the value of a scalar and not matrix, list, or any complex data structures.

vehicle	owner's surname
bike	Kowalski, Dąbrowski
motorcycle	Janik, Drzymała
car	Nowak, Olecki

table before normalization

vehicle	owner's surname
bike	Kowalski
bike	Dąbrowski
motorcycle	Janik
motorcycle	Drzymała
car	Nowak
car	Olecki

table in 1NF [ wróć na górę strony ]