Transcription of CIS 331: Introduction to Database Systems - vacic.org
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CIS 331: Introduction to Database Systems - vacic.org
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.
Vladimir Vacic, Temple University 3 Normalization: Reminder Ssn c-id Grade Name Address 123 cs331 A smith Main 123 cs351 B smith Main 123 cs211 A smith Main
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