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
Differentiate between natural join and outer join? Natural join is a binary operator which is written as (R * S) where as R and S are relations. The output of the natural join
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
Consider the relations EMP(ENO,ENAME,AGE,BASIC_SALARY) WORK_IN(ENO,DNO) DEPT(DNO,DNAME,CITY) Express the following queries in SQL (i) Find names of employees who work in a dep
Vertical Fragmentation- Vertical fragmentation groups together only those attributes in a relation that are used jointly by various important transactions. A vertical fragment is d
Synonyms It allows short names or alternative names for objects. Example : CREATE SYNONYM D30 FOR EMPD30; Now if we give command:
Question: One of the tasks a database management system must perform is to ensure that the data is still intact in the face of software and hardware failure. This task is known
Describe the types of attributes? Types of attributes: An attribute's category determines the type of values that are permitted in the attribute. For instance, the value vers
What are the problems if one were not to normalize? When do these problems surface? Ans: Database normalization, sometimes considered to as canonical synthesis, is
Question: (a) What is ODBC and what is its function? (b) What is Web application server, and how does it work from a database perspective? (c) What does e-commerce mean
What should be declared explicitly in the corresponding ABAP/4 Statements to access internal tables without header lines & why? Work Area. This is needed as the Work Area is
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