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.
Project Description: Need Point of Sale software for pizza restaurant. Delivery and take out service, client's database, inventory control, order history, last order, order from
Prepare a data flow diagram for computing the volume and surface area of a cylinder. Inputs are the height and radius of the cylinder. Outputs are the volume and surface area of th
What are the three classes of SQL expression? SQL expression consists of three clauses: Select From Where
What is a Database? To know what database is, we have to start from data, which is the basic building block of any DBMS. Data: Facts, figures, statistics etc. having no pa
HOW TO SOLVE THE LP Problems by simplex method?z=x1+-3x2+2x3
construct a B+ tree for the following set of key value (2,3,5,7,11,19,23,29,31) in ascending order where the pointers that will fit in one node is as follows:A. four B. six C. eigh
The First Normal Form (1NF) Let us first describe 1NF: Definition: A relation (table) is in 1NF if 1. There are no duplicate tuples or rows in the relation. 2.
A database is to be constructed to remain track of the teams and games of a sport league. A team has a number of players, not all of whom participate in every game. It is desired
Explain Dynamic Two-Phase Locking Here a transaction locks a data item instantly earlier than any operation is applied on the data item. After finishing all the operations on
Timestamps For Read operations: If TS (T) If TS (T) >= W-timestamp (Q), then the transaction T is trying to read a value of data item Q which has been written and committed
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