MIS 325 Lecture Notes - Lecture 10: Check Constraint, Boolean Expression, Referential Integrity

• School: UT-Austin
• Department: Management Information Systems
• Course: MIS 325
• Professor: Ayvaci

Document Summary

The relationships between tables are maintained correctly. In a foreign key table, each foreign key value must have a matching primary key value in the primary key table. To use declarative referential integrity (dri), define foreign key constraints. Deleting a row from the primary key table (causes orphaned rows) Inserting a row in the foreign key table. Updating the value of a foreign key. Updating the value of a primary key. Most denormalization occurs beyond the third normal form. If a table is updated infrequently, redundant data isn"t likely to cause problems. When a column from a joined table is used repeatedly in search criteria. Seldom need to query phone number without the area code. Seldom need to query city and state without the zip code. Allows users to insert, delete, and update rows without causing data inconsistencies. Insertion anomaly: adding new rows forces user to create duplicate data.