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.
How many levels can be viewed in Architecture of the database ? Architecture of the database can be viewed as three levels.
A table joined with itself is called ? A table joined with itself is known as self join table. Normal 0 false false false EN-IN X-NONE X-NONE
statical data
What is Trigger? Trigger: A database trigger is procedural code which is automatically executed in response to specific events on a particular table in a database. Triggers can
Add generation capabilities and/or tailor the built-in functionality of generator. This enables you to produce "all" the test data for the MySQL tables you produced in the previous
examples of fields in a database
When is UPDATE_STATISTICS command used? - When processing of large data is done, this command is used. - Whenever large number of modification, deletions or copy takes place
let us consider a table having 2200 records and the fixed size of the table to be considered as 25.then how many numbers of table is requredto perform horizontal fragmentation
System Design: An Object Oriented Approach Any software systems always try to change and evolve as technology and business rules evolve. The development of information systems
Backward Recovery (UNDO): In this system the uncommitted changes made by a transaction to a database are undone. Instead the system is reset to the last consistent state of databa
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