This is about relational algebra,
I have a table and im always having the problem of not being able to project what I want, but I think im almost right. For example, in this case I need to find all the pizzerias that female customers attend,
this is my algorithm
πname Frequents ⨝(πname σgender='female' Person) ,
in this case, I found all the names of each customer, and on the Frequents Table I want to display the pizzerias. How would I be able to do so?
I thought about doing
πpizzeria (πname Frequents ⨝(πname σgender='female' Person) Frequents or
πpizzeria σname = (πname Frequents ⨝(πname σgender='female' Person) Frequents
but it gives me an error. The tables are on the photo. Thank you in advance!
the whole group is on this pasteit file here