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:
Question 1 Describe the following- Clustering Indexing Question 2 Explain the following with suitable real time examples- Implementation of Integrity rules
Explain the Cartesian product: The Cartesian product operation does not need relations to union-compatible. The meaning of this is that the involved relations may have dissim
What is banker's algorithm? Banker's algorithm is a deadlock avoidance algorithm that is applicable to a resource-allocation system with multiple instances of each resource ty
What is Nested Queries explain in details? Nested Queries - A SELECT query could have subquery(s) in it. While a SELECT query having another SELECT query in it, is known as n
For each 1: n relationship type R involving two entities E1 and E2, we recognize the entity type (say E1) at the n-side of the relationship type R and contain primary key of the en
Create table employee and enter employee data in SQL? Consider the following relational schemas: EMPLOYEE (EMPLOYEE_NAME, STREET, CITY) WORKS (EMPLOYEE_NAME, COMPANYNAME, SAL
Describes the several relationship constraints through giving suitable example? Constraints on relationships: There are two kinds of constraints on relationships. 1) Mapping
An orchestra database consists of the following relations: CONDUCTS (conductor, composition) REQUIRES (composition, Instrument) PLAYS (Player, Instrument) Give the relational
(1) Insert into PERSON Violated constraint: - Key constraint Reason: - Primary key 1 already exists in PERSON. Dealing: - DBMS could ask the user to provide valid PER
Why are cursors necessary in embedded SQL? A cursor is an object used to store the output of a query for row-by-row processing through the application programs. SQL statements
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd