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));
Explanation on Data Sharing?
Question: a) What is Client/Server and what benefits can be expected from Client/Server systems? b) Explain what middleware is and what it does. Why would MIS managers be p
Question: In relation to distributed database answer the following questions: (i) Give a brief definition of distributed database. Support your answer with an appropriate di
Define the term- Actors and Data Stores Actors: An actor is the active object which drives data flow graph by producing or consuming values. Actors are attached to inputs a
What is a checkpoint? List the operations to be performed by the system when a checkpoint is to be taken. What does the recovery system do if there is a crash? There is large n
What is Hierarchical DBMS In HDBMS, data is structured in a tree like manner. There is a parent-child relationship between data items and the data model is very suitable for re
State the Design of Associations Before designing associations, it is essential to know the way they are used. For this, analysis of association traversals is required. It is
In the ER diagram, one example of subclassing is depicted following the Services entity. The subclasses Item Based and Time Based are created. The entity Services gains the attribu
What is a state chart diagram? State diagrams (State Chart Diagram) explain all possible states that a particular object can get into, and how object's state changes as result
Describe the Association: Design Before we describe association design let us define association "Association is set of links between two objects in the object model". It is
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