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Questions tagged [relational-database]

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. Relational database principles are the basis of a substantial part of data management theory and practice.

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. Relational database principles are the basis of a substantial part of data management theory and practice.

Targeted Questions

This tag is appropriate for questions concerning the relational model, relational and relational database implementation.

The SQL language is commonly used to specify relational database-designs and to define and solve relational database problems. However, DBMSs based on SQL are by definition not s and therefore not all SQL questions are relevant to the relational database tag. Questions specific to or its implementations should be tagged accordingly.

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Drupal data entry forms & db structure?

I'm trying to build a Drupal site in which users can input records containing data about "customers", "employees" and "sales". I would like to be able to create a form(s) which takes data about a sale/customer/employee and can be associated with a…
Nate
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Database design - keep record of chained entries

There are 3 cases 1) Basic Sender ---> Receiver 2) Parallel Sender ----> Receiver1 ----> ReceiverN 3) Chained Sender ----> Primary Receiver -----> Secondary Receiver1 -----> Secondary ReceiverN For 1) Basic…
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SQL Server: Can I create a 'synthetic' relation that has no indexing or constraint checking overhead?

What I wish to do is ensure that the foreign key relation is maintained in the database schema but for performance reasons, not enforce the constrain or incur any indexing overheads. It's purpose is purely to document the relationship. This is…
Tony O'Hagan
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How to create a route with Strapi 4?

I am trying to set a route. I followed a tutorial. Everything is happening in a folder inside the api folder. Route folder contains post.js file : 'use strict'; /** * post router. */ const { createCoreRouter } =…
Emilie Tossan
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is it possible to represent SQL RDB in XML?

Is it possible to represent a SQL Relational Database in XML? That is, how would XML handle the primary key -> foriegn key relationships? Or is it the case that XML can only represent the data in a single table? If it is possible, what would you do…
theangryhornet
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Different versions of 3NF?

I have a question on the definition of 3NF given by Chris Date in his book "Database Design and Relational Theory", page 78. The definition given in the book is: "A relvar R is in 3NF iff for every non-trivial FD X -> Y, either X is a superkey, or Y…
Louis
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How to read relational R:BASE data into a data frame(s) in R

My employer historically used R:BASE to store important information, but we no longer have access to the program and the data are sitting unused. It's four files (survey.rx1, survey.rx2, survey.rx3, and survey.rx4) that together form a relational…
Andrew Bade
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Is normalisation done on the primary key or on the candidate keys?

Im not sure about the correct definitions for normalisations, as primary key and candidate key are used interchangeably. I have come across these 2 definitions when trying to find a definition for 2NF and 3NF. Definitions 1: 2NF: "And every…
MohG
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Large Join Tables and Scaling

The Problem We have a rapidly growing database with several large join tables (currently in the billions of rows), but as these tables have grown the query time has suffered. The concern is that as more data is added to the tables linked by these…
Connor
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EntityFramework 4.1 Code first TPT and data integrity

Reading this article, http://weblogs.asp.net/manavi/archive/2010/12/28/inheritance-mapping-strategies-with-entity-framework-code-first-ctp5-part-2-table-per-type-tpt.aspx and doing a simple test myself, I feel that the database isn't very safe (from…
Sleeper Smith
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Change the value order of a column

i have a table that i created but inserted the wrong values. The actual table is much longer but this will suffice: id salary 1 100 2 200 3 400 4 300 and i would like to change the order of all the values of the column salary. So…
Rarowcun
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Update record in many-to-many linking table

I'm trying to figure out the best way of updating the linking table in a many-to-many relationship. I have two entities: Artist and Skill. The relationship between these two are many-to-many, given that an artist has 1 or 1+ skills and a skill can…
Che-Yi Kung
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Resetting all values in a column to zero at desired time using Postgresql

I’m working on an app that adds an increment of 1 to an int value, entries whenever a user clicks a button. I made use of Postgresql DBMS to store these values. I have done this successfully, however I want all values in the entries column of my…
joshua
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find all functional dependencies for attribute closure?

It is for a university assignment. I have to list all non-trivial functional dependencies that are applicable, while also trying to ensure that all tables in my schema are 3NF. I have created an ER Diagram & Relational Schema for my dataset. How can…
Iamclueless
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Why is my MySQL server not recognizing foreign key relations?

Well I've gotten 100+ answers to my questions on Stack Overflow, but it's time I finally registered and posted my first question! Alright, I have a table for the users of my program and 11 tables attached to this table with 1:1 and 1:M…
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