Another algebraic way to express a constraint is E1 E2 whe

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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 ? Suppose R is a relation with attributes A_1, A_2, .... A_n

Solution

2)Ans:

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