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));
Explain Transaction manager and their work? Transaction Manager: Ensure the database remains in a constant (correct) state despite system failure, and in which concurrent trans
Problem 1 What is a Data Warehouse? Mention its advantages 2 Explain the Top-Down and Bottom-up Data Warehouse development Methodologies 3 What is Data Transformation? Ex
Components of database manager The above functions are reached by the database manager. The major elements of a database manager are: Authorisation control: This mod
In case of entity integrity, the primary key may be declared? In a case of entity integrity primary key may be not Null.
Hello.I have database access assignment which consist of creation Form, Subform, Calculation, Macros
Inconsistent Analysis : The problem as given with transactions T1 and T2 where two transactions interleave to make incorrect result during an analysis by Audit is the instance of s
These are designed to reduce the effects of a database failure and make sure a database is restored to a consistent state if a failure does arise. Manual backup/restore utilities n
Benefits: It limits data access. It makes difficult queries look easy. It permits data independence. It presents dissimilar views of the similar data.
Why 'AS' clause is used in SQL ? 'As' clause is used for Rename operation. ‘AS' clause is used in SQL for rename operation. (e.g., SELECT ENO AS EMPLOYEE_NO FROM EMP)
For problems 1-4, give all candidate keys for the tables with FDs specified. Composite candidate keys must be put in parentheses, and candidate keys must be separated with commas
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