Top "Relational-database" questions

A relational database is a database consisting of relation variables (which are also called *relvars*, *R-tables* or just *tables*). The definition, manipulation and integrity rules of relational databases are based on relational operations equivalent to or similar to the Relational Algebra and Calculus.

What is the difference between 3NF and BCNF?

Can someone please explain the difference between 3NF and BCNF to me? It would be great if you could also …

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When and why are database joins expensive?

I'm doing some research into databases and I'm looking at some limitations of relational DBs. I'm getting that joins of …

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Still Confused About Identifying vs. Non-Identifying Relationships

So, I've been reading up on identifying vs. non-identifying relationships in my database design, and a number of the answers …

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Setting up table relations what do "Cascade", "Set Null" and "Restrict" do?

I want to start using table relations in a new project. After some googling I got 2 tables set up as …

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How can I find MAX with relational algebra?

Working with databases, how can I find MAX using relational algebra?

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Storing time-series data, relational or non?

I am creating a system which polls devices for data on varying metrics such as CPU utilisation, disk utilisation, temperature …

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MySQL query, MAX() + GROUP BY

Daft SQL question. I have a table like so ('pid' is auto-increment primary col) CREATE TABLE theTable ( `pid` INT UNSIGNED …

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Database normalization for School Management System

I am creating system for a school management system and come up with the attached database schema. Following is how …

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What are the uses for Cross Join?

A cross join performs a cartesian product on the tuples of the two sets. SELECT * FROM Table1 CROSS JOIN Table2 …

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Inner join with multiple tables

I have these four tables: PRODUCTS --------- PRODUCT_ID PRODUCT_TITLE (other fields) COLORS --------- COLOR_ID COLOR_NAME MATERIALS …

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