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.
Ask questApollo Hospitals (AH) is a popular medical service provider in Oman. AH wants to automate its business functions into an information system. The proposed information syst
Increased overheads on update : On the drawbacks side, it will need the system to ensure that all replicas of a relation are consistent. This shows that all the replicas of the rel
describe all the tables you have created. ?get table_name, status, num_rows, user_stats in user_tables system view ?get table_name, constraint_name, constraint_type in user_constr
Consider a typical sales invoice that would include the following information. Design a single table to hold all of the information required to store an invoice including this info
Recovery Techniques: After Reading the types of failures and database errors, let us talk about how to recover from the failures. Recovery can be complete using/restoring the previ
Law Associates is a large legal practice based in Sydney. You have been asked to design a data model for the practice based upon the following specification: The practice employs
What are the various states through which a transaction passes through in its lifetime? Briefly discuss all the events that causes transition from one state to another. Ans:
explain in details about one to one binary relationship
Give short note on the following terms:Dirty pages and ETL a.) Dirty pages. These are buffer pages which comprise modifications which haven't been written to disk. b.
Explain Growing Phase of locking Growing Phase: In this phase the transaction can only obtain locks, but cannot release any lock. The transaction enters the growing phase as so
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