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!
A model in database system mostly defines the organisation of data or structure and a set of operations on that data. Relational model is a easy model in which database is represented as a collection of "Relations", where every relation is represented by a two dimensional table. Therefore, because of its simplicity it is most commonly used. The following table shows a simple relation:
PERSON_ID
NAME
AGE
ADDRESS
1
Sanjay Prasad
35
b-4,Modi Nagar
2
Sharad Gupta
30
Pocket 2, Mayur
Vihar.
3
Vibhu Datt
36
c-2, New Delhi
Figure: A Sample Person Relation
Following are some of the benefits of relational model:
The easy tabular representation of database helps the user define and question the database conveniently. For example, you can simply find out the age of the person whose first name is "Vibhu".
As the database is a collection of tables, new data can be added and removed easily. Also, manipulation of data from several tables can be done simply using several basic operations. For instance, we can add a telephone number field in the table at Figure.
In relational databases the relational algebraic operations are used to influence database. These are mathematical operations and make sure accuracy (and less of ambiguity) as compared to other models.
Create centralized relational database using bottom up method. (a) Recognize a single un-normalized relation for the above scenario. (b) Recognize the primary key for
Process of Adjustment of inheritance During object design, inheritance is readjusted by rearranging classes and operations, and abstracting common behaviour.
The Enhanced Entity Relationship Diagram (ERD) produced with a drawing or case tool. Your EERD must use a ''standard'' notation style such as Crows Foot or Chen. Please note that t
What is deadlock? How can it be avoided? How can it be resolved once it occurs? Deadlock happens when two transactions are each waiting on a resource that the other transaction
Question 1 Suppose the employee employee id, name, designation, salary, attendance and address of any employee has to be stored in a database. You can store these data in a sequen
a. Define the term "deadlock". There are four conditions that must hold before deadlock is possible. Name them. b. Outline an algorithm that detects whether there is a deadlock.
Explain the paths in the association network We can analyze use of paths in the association network as given below: Calculate each operation Find associations whic
#questiononsider the following relation: CAR_SALE =(CAR_ID,oPTION_TYPE, Option_listpreice, Sale_date, Option_discountedprice)..
Mappings between Levels and Data Independence The 3 levels of abstraction in the database do not exist separately of each other. There must be some correspondence, or mapping
Order by clause By using this rows can be sorted It is used in the last portion of select statement By default it gets ascending order DESC: is used
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