Database Management Systems

Consider the following Schema: User $($UserId$,$ Name, Password$)$

Patent $($PatentNo$,$ PatentTitle, PatentContents, Diagrams, UserId $($Foreign Key$))$

Bid $($BidNo$,$ UserId $($Foreign Key$),$ PatentNo $($Foreign Key$),$ StartBid, FinalSellingPrice$)$

Give an expression in the relational algebra to express each of the following queries:

i$)$ Find all the bids that started at a price greater than $3000$ and finally sold at less than

$15,000.$ ii$)$ Find the patent no$.$ and patent titles for all the users who sold their patents

at a price greater than $2000.$

Find the output for the following:

PatentNo, PatentContents