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!
It defines that the tuple in one relation that refers to another relation must refer to an existing tuple in that relation. This constraint is states on two relations (not essentially distinct). It uses a concept of foreign key and has been dealt with in more factors in the next unit.
Example
In the example given above, the value of C^ in every R tuple is matching with the value of C# in some S tuple. If a tuple has values (A6, B2, and C4) is added then it is invalid as referenced relation S doesn't contain C4. Therefore, it will be a violation of referential integrity constraint.
What is the need for triggers? Triggers are useful mechanisms for alerting humans or for starting particular tasks automatically when particular conditions are met.
During the deletion of a tuple two cases can happen: Deletion of tuple in relation having the foreign key: In this type of case simply delete the desired tuple. For example, in
Define an operator that a Relational Algebra does not have Ans: Relational Algebra does not have Aggregation operators.
What are the benefits of document scanning? Document scanning, in addition to being cost-efficient, also enhances productivity. This service enhances security as you set the pa
Consider a database application that deals with an Employee relation with information such as SIN, name, data of birth (DOB), and DID (the ID of the department at which the employe
What is OLTP (Online Transaction Processing)? In OLTP - online transaction processing systems relational database design use the discipline of data modeling and generally follo
What are the advantages of creating a table from existing table?
In tuple relational calculus P1 → P2 is equivalent to ? A In tuple relational calculus P1→ P2 is equivalent to ¬P1 V P2. (The logical implication expression A B, meaning
why are older data models are being replaced by new data models
Explain the Query Processing Data Query Processing permits a user to report or analyze structured and unstructured data pulled from multiple data sources.
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