Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
If the deletion violates referential integrity constraint, then three alternatives are available:
Example:
Let R:
A#
B
C^
A1
B1
C1
A2
B3
C3
A3
B4
A4
C5
Q
C#
D
D1
D2
D3
Note:
1) '#' shows the Primary key of a relation.
2) '^' shows the Foreign key of a relation.
(1) Delete a tuple with C# = 'C1' in Q.
Violated constraint: - Referential Integrity constraint
Motive: - Tuples in relation A refer to tuple in Q.
Dealing: - Options available are
1) Decline the deletion.
2) DBMS may automatically delete all tuples from relation S and Q with C
# = 'C1'. This is known as cascade detection.
3) The one more option would result in putting NULL value in R where C1 exist, which is the initial tuple R in the attribute C.
What is Trigger? Trigger: A database trigger is procedural code which is automatically executed in response to specific events on a particular table in a database. Triggers can
An orchestra database consists of the following relations: CONDUCTS (conductor, composition) REQUIRES (composition, Instrument) PLAYS (Player, Instrument) Give the relational
Copy Data from One Database to another Database Project Description: I am having two MySQL databases with same tables. I just need to copy one Data from one to another dat
Write short notes on relational model The relational model uses a collection of tables to show both data and the relationships between those data. The relational model is an ex
notes about update opreation
explain the mapping constraints
In E-R Diagram how derived attribute are represented ? In E-R Diagram By Dashed ellipse derived attribute are represented.
Birla Institute of Technology & Science, Pilani Work-Integrated Learning Programmes Division Second Semester 2012-2013 EC-1 Assignment 2 (7.5% of the grade) Course No. : SS ZG
To do the division operation R1 ÷ R2, R2 should be a correct subset of R1. In the following example R1 have attributes A and B and R2 have only attribute B so R2 is a correct subse
Which operator is Cartesian product in relational algebra? Cartesian product in relational algebra is a binary operator. (It requires two operands. e.g., P X Q)
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd