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.
i have assignments I don''t have time to finish because of work and other assignments, can you help with this? All are from the book Darabase design, application development and a
Normal 0 false false false EN-US X-NONE X-NONE
Objectives After reading this part, you should be able to: Modify, create, and delete database schema objects; Update database using SQL command; Retrieve data f
Describe the definition of a transaction in SQL Ans: The SQL transaction starts implicitly. Transactions are finished by either Commit work that commits the transaction and st
A relationship set is a set of relationships of the similar type. For example, let consider the relationship among two entities sets course and student. Collection of all the in
Express the ways provided by MySQL for Pattern Matching? MySQL provides two kinds of pattern matching. 1) One is based on SQL patterns 2) Regular expressions.
What is Normalization? Database normalization is a data design and organization method applied to data structures based on rules that help building relational databases. In rel
Determine the term- Active values An active value is that has dependent values. Every dependent value registers itself with active value that contains a set of dependent values
Explain briefly concurrent task by taking an example. Concurrent Task- The concurrent occurrence of more than one event is called concurrent task. Operating systems can handl
Explain concurrency control? Concurrency control Oracles multiversion concurrency control varies from the concurrency mechanism used by some other data base vendors. Read
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