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!
Define entity integrity and referential integrity. How does SQL allow specification of these?
Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribute of R after that A cannot accept null values.
Referential Integrity Rule- In referential integrity, it is made sure that a value that appears in one relation for a given set of attributes as well appears for a particular set of attributes in another relation.
In SQL, referential integrity and entity integrity rules are implemented as constraints on the relation known as reference Key constraint and primary Key constraint correspondingly.
These constraints can be fixed with relation at the time of creation of the relations or after the creation of the relations by altering the definition of the relations. For instance:
Explain the cartesian product in Database Management System
Scenario 1: Power goes out after the first instruction. What happens?
Normal 0 false false false EN-US X-NONE X-NONE
What is trigger Triggers are statements that are implemented automatically by the system as the side effect of a change to the database.
What are the disadvantages of relational approach? Disadvantages of relational approach: • Substantial hardware and system software overhead • May not fit all business models •
Explain four causes for failures in data warehouse projects
Domain Constraints Domain constraints are primarily formed for defining the logically correct values for an attribute of a relation. The relation allows attributes of a relatio
Define garbage collection. Garbage may be formed also as a side effect of crashes. Periodically, it is essential to find all the garbage pages and to add them to the list of fr
i need help for assignment ..
What is the meaning of Data independence? Data independence means a programs that are not dependent on the physical attributes of data and a programs that are not dependent on
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