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!
Explain entity integrity and referential integrity rules within relational model. Show how these are realized in SQL?
Entity Integrity Rule - No primary key value could be null.
Referential Integrity Rule - In referential integrity, it is ensured in which a value which appears in one relation for a given set of attributes also appears for a certain set of attributes within another relation.
In SQL, entity integrity and referential integrity rules are implemented as constraints on the relation known as primary key constraint or reference key constraint corresponding. These constraints can be specified along with relation at the time of creation of the relations or after the creation of the relations through altering the definition of the relations. For instance:
CREATE TABLE DEPT
(DEPTNO NUMBER PRIMARY KEY,
DNAME VARCHAR2(15));
CREATE TABLE EMP
(EMPNO NUMBER PRIMARY KEY,
20
ENAME VARCHAR2(15),
JOB VARCHAR2(10),
DEPTNO NUMBER REFERENCES DEPT(DEPTNO));
Define Outer join Outer join - If there are any type of values in the one table that do not have corresponding value(s) in the other, in an equi-join which will not be selected
write short note on mobile database
The C_Artist application will be developed using the C language (C99 standards) and will be able to compile without warnings and link and run in the Swinburne computer laboratorie
Can a stored procedure call itself or recursive stored procedure? How much level SP nesting is possible? Yes. Because Transact-SQL supports recursion, you can write kept proced
Column Constraints: NOT NULL, UNIQUE, CHECK, PRIMARY KEY, DEFAULT, REFERENCES, On delete Cascade : Using this key whenever a parent row is removed in a referenced
Use of partial data by applications : In common, applications work with views rather than whole relations. Thus, it may be more appropriate to work with subsets of relations rather
What is a recovery scheme? An integral part of a database system is a recovery scheme that can restore the database to the reliable state that existed before the failure.
Question: (a) What are decision support systems, and what role do they play in the business environment? (b) Data mining is a knowledge discovery process of automated extr
Q. Explain data aggregatio n and discuss different design constraints. Sol. Aggregation One limitation of the E-R model is that it cannot express relationships amon
For the relations R and S given below: R S A B C 1 4 7 2 5 8 3 6 9
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