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.
Define Sequence A sequence is a set of integers 1, 2, 3 that are generated in order on demand. Sequences are regularly used in databases because lots of applications require ev
What is Stored Procedure? A stored procedure is a named group of SQL statements that have been previously formed and kept in the server database. Stored procedures accept input
what is attribute is attribute inheritance in dbms?
Redo Logs: Any database must have minimum two redo logs. These are the rules for the database; the redo logs record all modifies to the system objects or user objects. If any type
How is Oracle used in PL/SQL? Define the features of process and how they are defined? PL/SQL - PL/SQL is Oracle's procedural language (PL) superset of the Structured
The Transactions- A transaction is definite as the unit of work in a database system. Database systems that deal with a huge number of transactions are also termed as transaction p
What are the aggregate objects in the data dictionary? Views Match codes Lock objects.
Difference between Operating System and Database Security Security within the operating system can be executed at various levels ranging from passwords for access to system, t
What is an entity relationship model? The entity relationship model is a collection of basic objects known as entities and relationship between those objects. An
The insertion of a tuple in the aim of reference does not cause any destruction. Though, insertion of a tuple in the relation in which, we has the foreign key, for instance, in ASS
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