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!
It defines that no primary key value can be null. This is as the primary key is used to recognize individual tuple in the relation. So we will not be able to recognize the records uniquely containing null values for the primary key attributes. This constraint is specified on single individual relation.
Example: Let R be the Table
A#
B
C
Null
B1
C1
A2
B2
C2
B3
C3
A4
B4
A5
C5
Note:
1) '#' shows the Primary key of a relation.
In the relation R above, the primary key has null values in the tuples t1 & t3. NULL value in primary key is not allowed, therefore, relation instance is an invalid instance.
10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the delet
explain equi-join using illustration
HOW MANY TYPES OF VIEWS
Create an index for the table Client, field CLIENT_NO of Q ? Command: CREATE INDEX client_client_no ON client(client_no);
Why is need for the multiple access paths?
An entity type usually has an attribute whose values are distinct for every individual entity in the collection. Such an attribute is known as a key attribute and its values can be
Short Note on mid Square Method of hashing? Mid square method of hashing: In the method midsquare hashing, the key is squared and the address selected from the center of the s
What is DML Query Langauge? Data Manipulation Language (DML) - A data manipulation language is a language in which enables users to access or manipulate data as organized throu
1. Define each of the following IN YOUR OWN WORDS: (a) File: (b) Record: (c) Field: (d) Primary Key: (e) Secondary Key: 2. A travel agency wants t
1. Which relational algebra operations do not need the participating tables to be union-compatible? Ans: Join is the relational algebra operations that do not need the particip
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