Top "Relational-algebra" questions

Relational Algebra is an offshoot of first-order logic and of the algebra of sets that deals with relations (sets of tuples).

Relational Algebra equivalent of SQL "NOT IN"

Is there a relational algebra equivalent of the SQL expression NOT IN? For example if I have the relation: A1 | …

sql relational-algebra
Are these two relations compatible for a union operation?

I'm not sure if the following two relations are compatible for a union: R: <- schema name B 1 2 2 3 3 And: …

database relational-database union relational-algebra
Relational algebra to count rows

I wasn't sure quite what to call this problem but it's not exactly counting rows. Let's say we have the …

relational-database relational-algebra
Relational Algebra - Cartesian Product vs Natural Join?

I am studying for exams and am failing to find a solid criteria by which I can determine if the …

sql database-design relational relation relational-algebra
Aggregate Relational Algebra (Maximum)

I am currently working on a homework assignment that requires a selection to occur that pulls out an element containing …

sql aggregate aggregate-functions max relational-algebra
Clear explanation of the "theta join" in relational algebra?

I'm looking for a clear, basic explanation of the concept of theta join in relational algebra and perhaps an example (…

sql relational-database cartesian-product relational-algebra
Lossless Join and Decomposition From Functional Dependencies

Suppose the relation R( K, L, M, N, P), and the functional dependencies that hold on R are: - L …

join database-normalization relational-algebra functional-dependencies lossless
Natural join if no common attributes

What will natural join return in relational algebra if tables don't have attributes with same names? Will it be null …

relational-database relational-algebra
Can someone explain me how the cartesian product works in relational algebra

here it says Selection and cross product Cross product is the costliest operator to evaluate. If the input relations have …

cartesian-product relational-algebra
How to find all pizzerias that serve every pizza eaten by people over 30?

I'm following the Stanford Database course and there's a question where we have Find all pizzerias that serve every pizza …

relational-algebra relational-division