Another algebraic way to express a constraint is E1 E2 wher

Another algebraic way to express a constraint is E_1 = E_2, where both E_1 and E_2 are relational-algebra expressions. Can this form of constraint express more than two forms ?

Solution

The other algebraic way to express a constraint is E₁ = E₂. Here E₁and E₂are the relational-algebra expressions. Now we are expressing them in the two constraints:

E₁ – E₂= ø

E₁ E₂ AND E₂ E₁