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
Define various ways in which SELECT statement can be used for record selection Technology? SELECT gives you control over a number of aspects for record retrieval: 1) Which
Insertion Anomaly: Inability to show certain information-The primary key of the over relation be (enrolment number, Cno). Any new tuple to be inserted in the relation should have
Define garbage collection. Garbage may be formed also as a side effect of crashes. Periodically, it is essential to find all the garbage pages and to add them to the list of fr
Normalization :It is a process of examine the given relation schemas based on their primary key and Functional Dependencies (FDs) to achieve the properties Minimizing redun
Briefly explain the state diagram by taking one example. State Diagram - An object can be given a sequence of input instructions. The state of the object can vary depending u
What is System R? What are its two major subsystems? System R was intended and developed over a period of 1974-79 at IBM San Jose Research Center. It is a prototype and its pur
What is Trigger? Trigger: A database trigger is procedural code which is automatically executed in response to specific events on a particular table in a database. Triggers can
how design database from begining
What Is Sql? Structured Query Language (SQL) is a standard query language. It is usually used with all relational databases for data manipulation and definition. All the re
Define check point and its impact on data base recovery. Ans: There could be hundreds of transactions handled per minute, in a large on-line database system.
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