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!
Before we talk about the relational model in more detail, let us first define some very basic terms used in this model.
Tuple
Every row in a table shows a record and is called a tuple. A table containing 'n' attributes in a record is called n-tuple.
Attribute
The name of every column in a table is used to interpret its meaning and is known as an attribute. Every table is called a relation.
For instance, Figure shows a relation PERSON. The columns NAME, PERSON_ID, AGE and ADDRESS are the attributes of PERSON and every row in the table represents a separate tuple (record).
Relation Name: PERSON
PERSON_ID
NAME
AGE
ADDRESS
TELEPHONE
1
Sanjay Prasad
35
b-4,Modi Nagar
011-25347527
2
Sharad Gupta
30
Pocket 2, Mayur Vihar.
023-12245678
3
Vibhu Datt
36
c-2, New Delhi
033-1601138
Figure: An extended PERSON relation
Have database built but having problems with some questions that go with the database
Lock Based Protocol A lock is nothing but a mechanism that tells the DBMS whether a particular data item is being used by any transaction for read/write purpose. As there are t
what is lossless & dependency preserving decomposition ?
File Organisation And Its Types Just as arrays, trees, lists and other data structures are used to execute data Organisation in main memory, a number of planning's are used to
Improved performance: As the data is located near the site of its demand, and given the inherent parallelism because of multiple copies, speed of database access may be good for di
Define an operator that a Relational Algebra does not have Ans: Relational Algebra does not have Aggregation operators.
3 assignments combined in 1
Eliminate Columns Not Dependent On Key The Employee Relation satisfies - First normal form - As it has no repeating groups. Second normal form - As it do not have multi-a
Differentiate between various levels of data abstraction? Data Abstraction - Abstraction is the procedure to hide the irrelevant things from the users and represent the rele
why older data models are being replaced by new data models.
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