Answer all the following questions:

Explain the meaning of data Model?

Differentiate between the types of data model?

Differentiate some of the advantages and disadvantages of file processing systems?

Explain three of the advantages of the database approach?

Write a SQL statement to prepare a list with salesman name, customer name and their cities for the salesmen and customer who belongs to the same city.

salesman$\_$id

name

city

commission

$5001$

Ahmed

Amman

$0\mathrm{.}15$

$5002$

Ali

Cairo

$0\mathrm{.}13$

$5005$

Kamel

Algeria

$0\mathrm{.}11$

$5006$

Seko

Nigeria

$0\mathrm{.}14$

$5007$

Ruzaima

Kuala lumpur

$0\mathrm{.}13$

$5003$

Putri

Shah alam

$0\mathrm{.}12$

customer$\_$id cust$\_$name city grade salesman$\_$id

$3002$ Nick Rimando New York $1005001$

$3007$ Brad Davis New York $2005001$

$3005$ Graham Zusi California $2005002$

$3008$ Julian Green London $3005002$