dcm key

1. KEYS IN DBMS
PRESENTED BY,
KANTA ANURAG SHAOO : -220301120178
SUBHRASIS BISWAL : -220301120168

2. Introduction
Types Of Key
Conclusion
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CONTENTS

3.  Keys are used to ensure unique identification
of records in a database.
 They help in defining integrity constraints
and linking data between tables.
 Keys can be a combination of multiple
attributes or a single attribute.
 Their purpose is to provide every record with
a unique identity.
Introduction

4. Keys
Primary Key
Composite
Key
Super Key
Foreign Key
Candidate Key
Alternate Key
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5.  A Primary key is the column or columns that contain values that uniquely
identify each row in a table.
 The value of a primary key can’t be null.
 It should not allowed duplicate value
Primary Key

6.  A candidate key is an attribute or set of attributes that can
uniquely identify a tuple(A tuple in DBMS is a collection of
attribute values in which no two unique items
have the same name.).
 Except for the primary key, the remaining attributes are
considered a candidate key.
 The candidate keys are as strong as the primary key
Candidate key

7.  It is a column or group of columns that uniquely identify every row in a
table.
 A table can have multiple choices for a primary key but only one can be
set as primary key and rest are known as alternate key.
Alternate key

8.  A composite key is a candidate key that consists of two or
more attributes (table columns) that together uniquely
identify an entity occurrence (table row).
 Overall, composite keys are an important concept in database
design and can be used to ensure data integrity and create
relationships between tables.
Composite
key

9.  In the context of databases, a super key is a set of one or more attributes
or columns in a table that can uniquely identify each row in that table.
 Unlike a primary key, a super key may not be minimal, meaning it may
contain additional attributes beyond those necessary to uniquely identify
each row.
 It support null value.
Super key

10.  Foreign key are the column of an a table used to point to the
primary key.
 Foreign keys allow key values that are all NULL.
Foreign key

11.  In a database management system (DBMS), a key is a field or combination of
fields that uniquely identifies each record or row in a table.
 Keys are used to ensure the integrity of the data in a database by enforcing
rules that prevent duplicate records and maintain consistency.
 keys play a crucial role in a DBMS by ensuring data integrity and maintaining
consistency. They help to establish relationships between tables and enforce
referential integrity, which is important for maintaining the accuracy and
reliability of data in a database.
Conclusion

12. THANK YOU