You are working with a database that stores information about suppliers, parts and projects. The Supply relation records instances of a Supplier supplying a Part for a Project. The schema for the...

You are working with a database that stores information about suppliers, parts and projects. The Supply relation records instances of a Supplier supplying a Part for a Project.



The schema for the database used in this question is as follows: (note that primary keys are shown underlined, foreign keys in bold).

SUPPLIER (SNo, SupplierName, City)


PART (PNo, PartName, Weight)


PROJECT (JobNo, JobName, StartYear, Country)


SUPPLY (SNo, PNo, JobNo, Quantity)

Provide relational algebra (NOT SQL) queries to find the following information.

NOTE:
• You can use the symbols σ, π, etc or the words ‘PROJECT’, ‘RESTRICT’ etc as you prefer.

• You do not need to try to make efficient queries – just correct ones.

• Where you use a join, always show the join condition.


a. List the quantity of parts supplied on JobNo 4745.


b. List the weight of the Part named “Left-handed screwdriver”.


c. List the Project name and Part name of any Parts where fewer than 500 of the part has been supplied to a particular project.


d. List the name of any Suppliers who have supplied Parts to the Project called “New Academic Building” or to the Project called “Removal of Asbestos”.


e. List the name of any Suppliers who have supplied Parts to the Project called “New Academic Building” and to the Project called “Removal of Asbestos”.


f. List the names of Suppliers who have supplied the Part with the name “Fufful Valve”.


g. List the names of Projects that have had Parts supplied by “Insightly Co#” or a Supplier located in Dubai.
h. List the details of any supplier who has supplied parts to a project that stared in 2020 and (the project is) located in Singapore.


i. List the name of any part that was not used on a project that commenced in 2020.


j. List the name of any part that has been supplied to all projects that commenced in 2020.