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Session 3

Welcome: To session 3 - the 7th. learning sequence “Relational algebra “Recap : In the previous learning sequences, we

discussed some operators of relational algebra.Present learning: We shall explore the following

topic: - Example QueriesExample Queries

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Relational Algebra

Relational AlgebraRelational Algebra

A basic expression in the relational algebra consists of either one of the following: A relation in the database A constant relation

Relational Instances for the Relational Instances for the Purchasing SystemPurchasing System

The Supplier relation:

S-number S-name S-city

S100 Ahmed Amman

S200 Ali Jarash

S300 Kasim Irbid

S400 Jasim Aquaba

S500 Rana Amman

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The Part relation:

P-number

P-name

Color Price P-city

P1 TV Silver 300 Amman

P2 Camera Black 100 Jarash

P3 Video Black 200 Amman

P4 PC Silver 400 Irbid

P5 Printer Red 100 Irbid

P6 Scanner silver 150 Jarash

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The shipment relation:

S-number

P-number

Quantity

S100 P1 100

S100 P2 150

S100 P3 200

S100 P4 160

S100 P5 50

S100 P6 70

S200 P1 200

S200 P2 150

S300 P2 400

S400 P2 150

S400 P4 80

S500 P4 100

Example QueriesExample Queries Q1- Find The cities for all suppliers .

S-city (Supplier)

Example QueriesExample Queries Q1- Find The cities for all suppliers .

S-city

Amman

Jarash

Irbid

Aquaba

The result relation

S-city (Supplier)

Example QueriesExample Queries Q2- Find city for Ahmed.

Example QueriesExample Queries Q2- Find city for Ahmed.

Temp1 S-name = ‘Ahmed’ (Supplier)

Example QueriesExample Queries Q2- Find city for Ahmed.

Temp1 S-name = ‘Ahmed’ (Supplier)

S-number S-name S-city

S100 Ahmed Amman

Temp1

Example QueriesExample Queries Q2- Find city for Ahmed.

Temp1 S-name = ‘Ahmed’ (Supplier)

S-number S-name S-city

S100 Ahmed Amman

Temp1

S-city

AmmanResult

Result S-city (Temp1)

Example QueriesExample Queries Q3- Find Supplier number and name for

suppliers in Amman.

Example QueriesExample Queries Q3- Find Supplier number and name for

suppliers in Amman.Temp1 S-city= ‘Amman’ (Supplier)

Example QueriesExample Queries Q3- Find Supplier number and name for

suppliers in Amman.Temp1 S-city= ‘Amman’ (Supplier)

S-number

S-name S-city

S100 Ahmed Amman

S500 Rana Amman

Temp1

Example QueriesExample Queries Q3- Find Supplier number and name for

suppliers in Amman.Temp1 S-city= ‘Amman’ (Supplier)

S-number

S-name S-city

S100 Ahmed Amman

S500 Rana Amman

Temp1

Result S-number, S-name (Temp1)

Example QueriesExample Queries Q3- Find Supplier number and name for

suppliers in Amman.Temp1 S-city= ‘Amman’ (Supplier)

S-number

S-name S-city

S100 Ahmed Amman

S500 Rana Amman

Temp1

Result S-number, S-name (Temp1)

S-number

S-name

S100 Ahmed

S500 Rana

Result

Example QueriesExample Queries Q4- For each part supplied, find the part names

and the names of all cities storing these parts.

Example QueriesExample Queries Q4- For each part supplied, find the part names

and the names of all cities storing these parts.

Temp1 P-number ( Shipment )

Example QueriesExample Queries Q4- For each part supplied, find the part names

and the names of all cities storing these parts.

Temp1 P-number ( Shipment )

P-number

P1

P2

P3

P4

P5

P6

Temp1

Example QueriesExample Queries Q4- For each part supplied, find the part names

and the names of all cities storing these parts.

Temp1 P-number ( Shipment )Temp2 Part Temp1

Example QueriesExample Queries Q4- For each part supplied, find the part names

and the names of all cities storing these parts.

Temp1 P-number ( Shipment )Temp2 Part Temp1

P-number

P-name

Color Price P-city

P1 TV Silver 300 Amman

P2 Camera

Black 100 Jarash

P3 Video Black 200 Amman

P4 PC Silver 400 Irbid

P5 Printer Red 100 Irbid

P6 Scanner

silver 150 Jarash

Temp2

Example QueriesExample Queries Q4- For each part supplied, find the part names

and the names of all cities storing these parts.

Temp1 P-number ( Shipment )Temp2 Part Temp1Result P-name, p-city(Temp2)

P-name P-city

TV Amman

Camera Jarash

Video Amman

PC Irbid

Printer Irbid

Scanner Jarash

Result

Example QueriesExample Queries Q5- For each part supplied, find the part numbers

and names of all cities supplying the parts.

Example QueriesExample Queries Q5- For each part supplied, find the part numbers

and names of all cities supplying the parts.

Temp1 Shipment Supplier

Example QueriesExample Queries Q5- For each part supplied, find the part numbers

and names of all cities supplying the parts.

Temp1 Shipment Supplier

S-number P-number

Quantity

S-name

S-city

S100 P1 100 Ahmed Amman

S100 P2 150 Ahmed Amman

S100 P3 200 Ahmed Amman

S100 P4 160 Ahmed Amman

S100 P5 50 Ahmed Amman

S100 P6 70 Ahmed Amman

S200 P1 200 Ali Jarash

S200 P2 150 Ali Jarash

S300 P2 400 Kasim Irbid

S400 P2 150 Jasim Aquaba

S400 P4 80 Jasim Aquaba

S500 P4 100 Rana Amman

Tem

p1

Example QueriesExample Queries Q5- For each part supplied, find the part numbers

and names of all cities supplying the parts.

Result P-number, S-city ( Temp1 )

Temp1 Shipment SupplierP-number

S-city

P1 Amman

P2 Amman

P3 Amman

P4 Amman

P5 Amman

P6 Amman

P1 Jarash

P2 Jarash

P2 Irbid

P2 Aquaba

P4 Aquaba

P4 Amman

Result

Example QueriesExample Queries Q6- Get supplier numbers for suppliers who

supply part p2

Example QueriesExample Queries Q6- Get supplier numbers for suppliers who

supply part p2

Temp1 p-number = ‘p2’ (Shipment)

Example QueriesExample Queries Q6- Get supplier numbers for suppliers who

supply part p2

Temp1 p-number = ‘p2’ (Shipment)

S-number P-number Quantity

S100 P2 150

S200 P2 150

S300 P2 400

S400 P2 150

Temp1

Example QueriesExample Queries Q6- Get supplier numbers for suppliers who

supply part p2

Temp1 P-number = ‘p2’ (Shipment)Result S-number ( Temp1 )

S-number

S100

S200

S300

S400

Result

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Relational AlgebraRelational Algebra

Summary: In this learning sequence, we discussed

some example queries about purchasing system.

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END