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!
Define entity integrity and referential integrity. How does SQL allow specification of these?
Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribute of R after that A cannot accept null values.
Referential Integrity Rule- In referential integrity, it is made sure that a value that appears in one relation for a given set of attributes as well appears for a particular set of attributes in another relation.
In SQL, referential integrity and entity integrity rules are implemented as constraints on the relation known as reference Key constraint and primary Key constraint correspondingly.
These constraints can be fixed with relation at the time of creation of the relations or after the creation of the relations by altering the definition of the relations. For instance:
Describe five main functions of a database administrator. Ans: A database administrator (DBA) is a person who is accountable for the environmental aspects of a database. Genera
What is Primary key? Primary Key - Primary key is one of the candidate keys which uniquely identifies each row in the relation.
Explain entity integrity and referential integrity rules within relational model. Show how these are realized in SQL? Entity Integrity Rule - No primary key value could be nu
Define the basic operations of the relational algebra? Ans: Basic operators of relational algebra are: 1. Union (∪) - Selects tuples which are in either P or Q or in bot
A step-wise distributed database design methodology Following is a step-wise methodology for distributed database design. (1) Examine the nature of distribution. Find out wh
What are the causes of bucket overflow in a hash file organization? What can be done to reduce the occurrence of bucket overflow? When a record is inserted, the bucket to that
Explain Network Model in DBMS? Network Model - It was formalised within the late year of 1960s through the Database Task Group of the Conference on Data System Language (DBTG
Explain Record Based Logical Models? Record-Based logical Models: Also define data at the conceptual and view levels. Unlike object-oriented models, are used to state overall
(a) Design a query plan for the following distributed query: An application at site B wants to compute a join of STUDENT ? Id=StudId TRANSCRIPT where STUDENT (Id,Major) is at site
Database Manager It is the interface among low-level data, queries and application programs. Databases typically need a large amount of storage space. It is kept on disks, as
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