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
A Structure of a dependency diagram
sql is relationally complete-justify
Is it mandatory to declare all the tables in Report by the key word tables for all the tables that exist in the structure of LDB, and are being explained in the Database part of LD
Differentiate between logical database design and physical database design. Show how this separation leads to data independence? Basis Logical Databas
What is a Transaction? A transaction is an event which happens on the database. Generally a transaction reads a value from the database or writes a value to the database. If y
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
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
What is a primary key? Primary key is chosen by the database designer as the principal means of identifying an entity in the entity set.
Which is an advantage of view? The Advantages of view is Data security, Derived columns and Hiding of complex queries
what are information system hirarchy?
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