Relational Theory

• Topics

  Started by

  Posts

  Last post

• Question about Conceitual Database Model

  Hi! I am creating a database for an ecommerce and among the entities there are Customer, Shopping C…

  dougsan

  2 replies

  9 months ago

  By: Jeff Moden

• RIGHT-JOIN table not fetching all rows in WHERE clause

  I'm trying to add an additional table (hrxoreturn) with RIGHT JOIN to return all records either wit…

  clai_shock008

  7 replies

  1 year, 9 months ago

  By: jcelko212 32090

• Multiple column primary key or guid

  All, I would appreciate views on the following: When the unique combination for table involves seve…

  as_1234

  6 replies

  3 years, 2 months ago

  By: MMartin1

• Entity Relationship diagram - Path and Node entities

  I have two tables; a path table that contains distinct paths and a node table that contains distinc…

  boolean

  4 replies

  4 years, 8 months ago

  By: Jeff Moden

• A simple example which, after 15 years of relational design work, still breaks my brain - phone numbers

  Every so often I find myself needing to build schema for something which has very little complexity…

  Don Halloran

  11 replies

  5 years, 5 months ago

  By: nova

• Defining keys as sets that must not intersect instead of scalar values that must not be equal

  I have been doing a lot of thinking about data models for the last couple of weeks. I have, just no…

  Don Halloran

  37 replies

  6 years, 11 months ago

  By: Lynn Pettis

• Is My Foreign Key Table Unnecessary?

  I'm sure this has been addressed many times here but none of the search terms I've tried have surfa…

  Phil Stratford

  9 replies

  6 years, 11 months ago

  By: HappyGeek

• Constraint help

  I am new to SQL and am playing around with it to familiarize myself with it before taking a class t…

  fweymouth

  4 replies

  7 years, 1 month ago

  By: Thom A

• Is having a lookup table that is for multiple entities a common practice?

  I've been programming and designing databases of various sorts for several years. And I've been on …

  Doctor Who 2

  32 replies

  7 years, 10 months ago

  By: TomThomson

• How to make ERD design for image below between section and lab and courses and instructors and days&time

  I need to make ERD database design for university database my details as following table year and t…

  ahmed_elbarbary.2010

  1 replies

  7 years, 11 months ago

  By: x

• Third Normal form & some related things

  With the third normal form, is there any kind of general "rule of thumb" For when you should or sho…

  Steven.Grzybowski

  2 replies

  8 years, 4 months ago

  By: Jeff Moden

• IBM Hierarchical IMS Database model to RDBMS, options ?

  Hi COBOL / IMS Db migration to SQL Server / .NET, Need help on how to DATA Model from segments to…

  Rankerg

  25 replies

  8 years, 7 months ago

  By: Rankerg

• Movie Rental Database

  Based on this description did I create the Class Diagram Correctly? Please open the attachment. Gen…

  sasansamani

  5 replies

  8 years, 10 months ago

  By: MMartin1

• Add allowance to employee table is wrong or true

  Hi guys I have problem i need to make erd relation entity between employee and allowance Employee t…

  ahmed_elbarbary.2010

  4 replies

  9 years, 2 months ago

  By: HappyGeek

• Employeee Benefits Database

  Can somebody tell what is the bridge class between Employee and Benefit? Also what is the Multiplic…

  sasansamani

  5 replies

  9 years, 2 months ago

  By: HappyGeek