Briefly discuss the different types of update operations on relational database show an example of a violation of referential integrity in each of the update operation For each of the update operations Insert Delete and Update Database Management Systems 10CS54 VTU notes 8 Marks Dec Jan 2013 DecJan 2014

The Eduladder is a community of students, teachers, and programmers just interested to make you pass any exams. So we solve previous year question papers for you.
See Our team
Wondering how we keep quality?
Got unsolved questions?

Ask Questions
Database-Management-System-10CS54-VTU-unit-3-->View question


Briefly discuss the different types of update operations on relational database. show an example of a violation of referential integrity in each of the update operation For each of the update operations (Insert, Delete, and Update), . : Database Management Systems - 10CS54 VTU notes 8 Marks (Dec /Jan 2013, Dec/Jan 2014)

we consider what kinds constraint violations may result from applying it and how we might choose to react


By:anonymousguy7799

Taged users:


Likes:
Be first to like this question

Dislikes:
Be first to dislike this question

Talk about thisDelete|Like|Dislike|


Answers

Insert: • domain constraint violation: some attribute value is not of correct domain • entity integrity violation: key of new tuple is null • key constraint violation: key of new tuple is same as existing one • referential integrity violation: foreign key of new tuple refers to non-existent tuple Ways of dealing with it: reject the attempt to insert! Or give user opportunity to try again with different attribute values. 

Delete: • referential integrity violation: a tuple referring to the deleted one exists. Three options for dealing with it: • Reject the deletion • Attempt to cascade (or propagate) by deleting any referencing tuples (plus those that reference them, etc., etc.) • modify the foreign key attribute values in referencing tuples to null or to some valid value referencing a different tuple
Update: • Key constraint violation: primary key is changed so as to become same as another tuple's • referential integrity violation: o foreign key is changed and new one refers to nonexistent tuple o primary key is changed and now other tuples that had referred to this one violate the constraint 

Nikhil-bharadwaj

Likes:
Be first to like this answer

Dislikes:
Be first to dislike this answer
Talk about this|Once you have earned teacher badge you can edit this questionDelete|Like|Dislike|
------------------------------------

Can you help us to add better answer here? Please see this



Not the answer you're looking for? Browse other questions from this Question paper or ask your own question.

Join eduladder!