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).

How to fetch distinct values with arel/relational algebra

I'm doing my best to bend my brain around arel and the relational algebra behind it, but how to represent …

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How to represent GROUP BY with HAVING COUNT(*)>1 in relational algebra?

For an exam, I am asked to get the list of clients having more than one rent, both as an …

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What is TRC and DRC in DBMS?

What is tuple relational calculus (TRC) and domain relational calculus (DRC)? How do they differ with relational algebra? I am …

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Represent a subquery in relational algebra

How do I represent a subquery in relation algebra? Do I put the new select under the previous select condition? …

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Relational Databases and Mathematics?

Can anyone suggest resources that take a mathematical approach to relational databases? Essentially relational algebra I'd guess. I have a …

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Converting aggregate operators from SQL to relational algebra

I have several SQL queries written that I want to convert to relational algebra. However, some of the queries use …

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Couchdb join two documents using key

I have two documents one with tree structure and the other one relation to the first doc. Im trying to …

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relational algebra expression for "is null"

What is the relational algebra expression of the query below? I couldn't find the expression for "Is Null". SELECT reader.…

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How to represent "not exists" in relational algebra?

How do I represent the SQL "not exists" clause in relational algebra?

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Unique constraint over multiple tables

Let's say we have these tables: CREATE TABLE A ( id SERIAL NOT NULL PRIMARY KEY ); CREATE TABLE B ( id SERIAL …

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