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 the aim of object design The aim of object design is to identify object which the system contains and the interactions among them. The system implements specification
Domain Constraint It shows that each attribute in a relation has to contain an atomic value only from the corresponding domains. The data types associated with commercial RDBMS
Storage Of Database On Hard Disks At this point, it is worthwhile to note the difference among the terms file Organisation and the access method. A file organisation shows to t
Views in relational algebra: 1. Basic expression contains either a) A relation in the database. b) A constant relation. 2. General expressions are madde out of sma
Question: Data Mining is the process of extracting knowledge hidden from large volumes of raw data. (a) Using a suitable example, illustrate how Data Mining can be useful t
First Normal Form and second normal form First Normal Form (1NF) A relation is said to be in 1NF if it having no non-atomic values and each row can give a unique combinat
Sequences Sequences: Automatically produce unique numbers Are sharable Are typically used to make a primary key value Replace application code Speed up t
Copy Data from One Database to another Database Project Description: I am having two MySQL databases with same tables. I just need to copy one Data from one to another dat
What are the key features of Oracle? Key features of Oracle are as follows: • Read Consistency • Concurrency • Locking Mechanisms • Quiesce Database • RAC • Portability
lock and types of lock
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