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http://www.vacic.org/lib/sql/notes/normal.pdf
NormalizationCIS 331: Introduction to Database SystemsVladimir Vacic, Temple University2 Normalization: Reminder Why do we need to normalize? To avoid redundancy (less storage space needed, and data is consistent) To avoid update/delete anomaliesVladimir Vacic, Temple University3 Normalization: ReminderSsn c-id GradeNameAddress123 cs331 Asmith Main123 cs351 Bsmith Main123 cs211 Asmith Main Clearly, Name and Address are redundant(larger relation + you have to update 3 rows to update the Address)Vladimir Vacic, Temple University4 Normalization: Reminder Insertion anomaly:Cannot make a record Jones address because he is not taking any classesSsn c-id Grade Name Address123 cs331 Asmith null null jones ForbesVladimir Vacic, Temple University5 Normalization: Reminder Delete anomaly:Cannot delete Shmoo s enrolment without loosing his address as wellSsn c-id GradeNameAddress123 cs331 Ajones 123 Main124 cs351 Bsmith 124 Broad125 cs211 Ashmoo 42 PennVladimir Vacic, Temple University6 Normal Forms First Normal Form 1NF Second Normal Form 2NF Third Normal Form 3NF Fourth Normal Form 4NF Fifth Normal Form 5NF(so far conveniently named) Boyce-Codd Normal Form BCNFV ladimir Vacic, Temple University7 First Normal Form (1NF) 1NF: all attributes are atomic( no repeating groups )AnneMichaelRumpelstiltskinPeterMaryJohn SmithFirst NameLast NameNot in 1 NFVladimir Vacic, Temple University8 First Normal Form (1NF)A
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