Cardinality and Determinents

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Cardinality – Combination Join and Occurrences

City Table
Country Code	City Code	City Name
101	201	New York
102	202	Hyderabad
102	203	Mumbai
103	204	London
105	205	Tokyo

Join

Country Table
Country Code	Country Name
101	US
102	India
103	UK
104	Australia

·      Joining using Country Code column from both of the tables

1.1   to     1.1 - Inner Join - Fetches only matching records

Country	City
US	New York
India	Hyderabad
India	Mumbai
UK	London

0.1   to     1.1 - Right outer Join - Fetches matching records + Right side non-matching records

Country	City
US	New York
India	Hyderabad
India	Mumbai
UK	London
	Tokyo

1.1   to     0.1 - Left outer Join - Fetches matching records + Left side non-matching records

Country	City
US	New York
India	Hyderabad
India	Mumbai
UK	London
Australia

0.1   to     0.1 - Full Outer Join - Fetches matching records + Left side non-matching records + Right side non-matching records

Country	City
US	New York
India	Hyderabad
India	Mumbai
UK	London
Australia
	Tokyo

Occurrences

1.1to 1.1- One to One

City	STD code
Delhi	011
Mumbai	022
Kolkata	033
Chennai	044
Hyderabad	040
Bangalore	080

1.1to 1.n - One to Many

Country	City
US	New York
US	Washington
India	Mumbai
India	Hyderabad

1.n  to 1.1 -  Many to One

Student	Teacher
Student A	Teacher B
Student B	Teacher B
Student C	Teacher B

Employee	Manager
Drew	Tom
Micky	Tom
Julie	James
Rocky	James

1.n  to 1.n  - Many to Many

Student	Subject
Student A	Maths
Student B	Science
Student C	Science
Student C	Maths

Determinants 

A determinant can define the set of database columns (query items) that uniquely identify a set of data. Determinants are most closely related to the concept of keys and indexes in the data source and are imported based on key and index information in the data source. We recommend that you always review the determinants that are imported.

Sales Area Table

State	City	Store	Employee
CA	San Fransisco	Bayside	Bill Withers
CA	San Fransisco	Bayside	Elaine Wiley
CA	San Fransisco	Bayside	Jack Tom
CA	Reading	Wallmart	Gomez
CA	Reading	Wallmart	Clark

Budget Table

Store	Month	Sales Target
Bayside	Jan 2013	200,000
Wallmart	Jan 2013	150,000

If you join above tables, then result is as below without determinants

Wrong Result

State	City	Store	Sales Target
CA	San Fransisco	Bayside	200,000
CA	San Fransisco	Bayside	200,000
CA	San Fransisco	Bayside	200,000
CA	Reading	Wallmart	150,000
CA	Reading	Wallmart	150,000

If you join above tables, then result is as below with determinants

Right Result

State	City	Store	Sales Target
CA	San Fransisco	Bayside	200,000
Pensulvania	Reading	Wallmart	150,000