Requirements.txt

Let a sample data base application , called [ VNC Channals ] 
Keep track of a channal , program , ads , person , department , season , episode , studio and device .
Data Requirements for VNC channals :
- Each channal has a unique Frequency , FEC , Polarisation , Desqription , location , Name and Type .
- channal show program and Ads .
-  Each Ads has unique sponser_name , duration , price per minute and cost . 
- Each program has a unique ID , Desqription and Name .
- Each program has season .
- season has unique number , start_date and end_date.
- season has episode .
- Each episode has content , description , title and number .
- program including sport and news program 
Hence , we use a disjoine type [ program ] that is a subset of the disjoine of news and sport entity type .
- Each sport program display a live_match.
- Each news program display a live_news .
- Each live_match has a date , start time , end time , home team name , away team name , away team score and home team score .
- Each live_news hase a content , source and date .
- Each channal has studio , department and person .
- Each studio has unique Studio_id and location . 
- Each studio use Devices. 
- Each Devices has unique serial_number , model , cost and date_of_purches .
- Each department has unique name and location .
- Each person has unique ssn , first_name , mid_name , last_name ,  birth_date , gender , age and nationaity .
- person is either a manager or a stuff or a guest .
Hence, we use a disjoine type [person] that is a subset of the disjoine of manager and stuff and guest entity type .
- Each manager has monthly_salary and mange a department .
- Each guest has Hourly_salart .
- Each staff has a job_title and monthly_salary and work on department .
- staff including director , presenter and engineer .
Hence , we use a disjoine type [ staff ] that is a subset of the disjoine of director , presenter and engineer entity type . 
- Each director directing a season .
- Each presenter present a program .
- Each engineer has eng_type and control a device .