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));
What is a cascading update? Referential integrity constraints needs that foreign key values in one table correspond to primary key values in another. If the value of the primar
In E-R diagram how generalization is represented? in E-R diagram generalization is represented by Triangle shape.
i want notes on this topic
Run the following queries. For each query show 1) What you expect the output to be based upon the data 2) the SQL code and 3) the output running the query in Oracle. 1. Show all c
The ABC Bank authority now wants to create a database for their customers. So you are requested to modify your program of Assignment A3 as follows. The main program first displa
Answer SQL Queries to extract data from data tables and questions on mapping conceptual data models into relational data model.
milestone assignment
Removing a Synonym: DROP SYNONYM D30;
What are the function of DBA?
Provide Examples of different types of Time and Date formats. It's most common store dates using a dash (-) as a colon (:)and the delimiter as the time delimiter. The given fo
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