The document discusses database management systems, focusing on relational algebra and various join operations. It defines key operations such as selection, projection, and join, including types like theta join, equi join, natural join, and outer join. Each join type is explained with its characteristics and how it combines data from two relations.

1. DATABASE MANAGEMENT SYSTEMS
PRESENT BY:
RUSHIT BHADANIYA

2. RELATIONAL ALGEBRA
 Introduction
 Join Operation

3. INRODUCTION
 Relational Algebra is a procedural query
language.
 It consists of a set of operations that take one
or two relations as input and produce a new
relation as their result.

4. FUNDAMENTAL OPERATION IN RELATIONAL
ALGEBRA ARE:
 Selection
 Projection
 Union
 Set Difference
 Cartesian Product
 Join

5. JOIN
 The JOIN operation is denoted by the R|X|S symbol
and is used to compound similar tuples from two
Relations into single longer tuples.
 Join operation is generally the cross product of two
relation.
 The notation used is
 R JOIN join condition S

6. TYPES OF JOIN
 Theta Join
 Equi Join
 Natural Join
 Outer Join

7. EQUI JOIN
 For whatever JOIN type (INNER, OUTER, etc), if
we use ONLY the equality operator (=), then we say
that the JOIN is an EQUI JOIN

8. THETA JOIN
 This is same as EQUI JOIN but it allows all other
operators like >, <, >= etc.

9. NATURAL JOIN
 The JOIN involves an equality test, and thus is
often described as an equi-join.
 Such joins result in two attributes in the resulting
relation having exactly the same value.
 A natural join will remove the duplicate attributes.

10. EXAMPLE

11. OUTER JOIN
There are three forms of the outer join, depending on
which data is to be kept.
 LEFT OUTER JOIN - keep data from the left-hand
table and if there are no columns matching in the
right table, it returns NULL values.
 RIGHT OUTER JOIN - keep data from the right-
hand table and If there are no columns matching in
the left table, it returns NULL values.
 FULL OUTER JOIN - keep data from both tables
and it returns row from either table when the
conditions are met and returns NULL value when
there is no match.

15. THANK YOU