self doubt

Question

We know Relational algebra(RA) and Relational calculas(RC) are equivalent in power...Can we say power of SQL and relational algebra are same??

I think no because we have some aggegate function, order by etch which is not done by relational algebra but all the RA operations can be done in SQL so can say SQL has highest power than RA/RC????

Answer 1

There are two GATE questions based on the same. Please refer the links below. Relational algebra is equivalent to both TRC and DRC with safe expressions i.e expressions that do not have conditions like this X$\notin$ E(X). And comparing SQL and Relational Algebra, SQL has three features that fundamentally distinguish it from relational algebra: namely, grouping, arithmetic operations, and aggregation

https://gateoverflow.in/825/gate2002-1-20

https://gateoverflow.in/3554/gate2006-it-15

Comments

Thanks:)

That I know that RA is equivalent to safe RC

but can we say power of SQL is same as RA???

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No, as you pointed out SQL is more powerful.

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I was still bit confuse...Thanks for the confirmation:)