All Questions
Tagged with erd database-design
316 questions
0
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41
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Could a Tool Like ChartDB Work for MongoDB Schema Visualization?
I’m one of the developers behind ChartDB, an open-source tool for database schema visualization, particularly useful for relational databases (RDBMS). Our tool helps users generate ER diagrams to map ...
- 11
0
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0
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22
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Need help with ER diagram for my pet project
Right now, I have started to learn more about databases. One of the topics that I have more questions about is the relationships between tables. For example, I am currently trying to create an ER ...
2
votes
1
answer
186
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Please help me understand this problem about cardinality
Me and my friend are in the process of creating an ER diagram for a professional soccer league, we are both very new to Database so we aren't sure if everything we do is correct.
When creating a ...
- 23
0
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1
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35
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Chen ERD: What improvement could I make? Can relationship `RECEIVES` be omitted since entity `INVOICE` is a weak entity of `CAR`?
Assumptions:
A salesperson may sell many cars, but each car is sold by only one salesperson.
A customer may buy many cars, but each car is bought by only one customer.
A salesperson writes a single ...
- 1
0
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1
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30
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How to implement historical data with this EERD?
I am looking for a way to implement historical data with the following EERD (what I have tried, below the image):
What have I tried?
Temporal tables
Didn't work because I use MySQL and it has no ...
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0
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39
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Associative relationship for "manager working term"
I am creating ERD following some database design requirements.
This specific part on the ERD is what I am trying to represent.
I made the MANAGEMENT entity because it's related to DATE_ACCEPTANCE, ...
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0
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1
answer
250
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Should I Use a Composite Key or a Single-Column Primary Key in my Entity Relationship Diagram?
I am designing an Entity Relationship Diagram (ERD) for a database that includes a table with variants annotated by different tools. In this table, each variant is annotated by a specific tool, and ...
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3
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132
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2nd Normal Form ERD thoughts
This ERD has completed 2nd Normal Form normalisation, as every table has a primary key, the data is atomic, there are no repeated groups, and there is no partial key dependency.
What are your thoughts?...
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0
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49
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feedback and improvements for London Autos ERD
London Autos has several locations within London and its surroundings, from its humble beginning a decade ago in an east London garage, the business has expanded into a multi-million-pound business. ...
amz
2
votes
1
answer
157
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Deleting a row in one table should also delete the corresponding rows in another table
I have these tables: station and water_types. The user may only have one station, and if the user wants to delete the station, the corresponding water_types must also be deleted. In a station, there ...
- 125
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0
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24
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Help needed with database design
I am designing a real estate database to keep records of plots (lands). There are many aspects to it like sale deeds, buyers, sellers, etc. But specifically, the bit where I've got stuck and need your ...
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1
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42
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ER Diagram for Missed Visits
I have to design an ERD for a hypothetical scenario. In the scenario, the nurse at a rural clinic needs to get summary data regarding patient visits so she can reschedule canceled or no-show visits.
...
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3
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1
answer
217
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Need help with first ER diagram
This is my first time doing the diagram. My teacher isn't the best at helping out or responding to questions so I've come here to ask for further assistance. I think I've mostly got it correct, but ...
- 31
0
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1
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34
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ERD Review, Employee travel lump-sum payment based on rank
I'm building application for employee official travel with lump-sum payment based on the employee group or echelon they have and I need a little help how to store the data correctly, as the problem im ...
-1
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1
answer
49
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What arrow is used to specify the relationship between a junction table and the FK tables [closed]
This is part of my first database design. I am unsure what type of arrow to use to describe the relationship:
The tables are parking space, parking space features, and features.
I am unsure of how to ...
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3
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3
answers
1k
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Is it ok to have repeated values in some of the columns and similar columns in two separate tables?
I'm trying to create database in which I could store thousands of job postings. I put here 3 sample records of these job postings so that you could better understand how everything looks like:
Every ...
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0
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157
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ERD Review for Chipotle Order System
Attached is the ERD for my attempt at creating an ERD of Chipotles order system. I've been trying to learn how to make good ERD for database design and wanted to get some feedback.
I'm confused on ...
1
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0
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61
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Table for an Appointment App
experts,
I am building out an appointment scheduler application. I am seeking advice on how best to tackle this issue.
I am building out my ERD and I am the point where I will be creating a ...
3
votes
1
answer
870
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If an entity's primary key must contain a foreign key, does that make the entity weak?
I'm currently learning about strong and weak entity types in the context of RDBMS. While reading, I came across this statement:
"A weak entity is dependent on a strong entity to ensure its ...
- 141
2
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0
answers
226
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My relational schema and a few questions about relations and duplicate values in columns
I'm trying to create database in which I could store thousands of job postings. I put here 5 sample records of these job postings so that you could better understand how everything looks like:
Now, ...
- 65
3
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0
answers
60
views
Help Creating a 'Complex' ERD
I am stuck on how to represent the relationships I need correctly. I have a
Produce table. Each type of produce—e.g., 'lettuce'—has one or more quantity suffixes that can be associated with it, e.g., '...
- 39
1
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1
answer
633
views
How to implement disjoint (nonoverlapping) subtype with total completeness in MongoDB?
I designed an entity relationship diagram (ERD) with the goal of creating two child entities (INSTITUTION and SPACECRAFT) of a parent entity (LOCATION), which is distinguished depending on the value ...
- 113
1
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0
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926
views
Can a foreign key be a primary key?
I want to know the relationship takes, teaches, advisors tables underlined attributes are foreign key or primary key? or both?
- 11
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1
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76
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There are 2 ERD Designs, and one has a strange combination. I am told both are correct. why?
One of the designs seems clear: A REQUESTEDPRODUCT is picked from STOCK (which has many locations). The primary key is a composite key of 4 foreign keys.
The other design is more unclear. The "...
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0
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981
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Is this ER diagram correct?
I am working on my first ER diagram, for a clothing brand case study. I was wondering if my work is correct. Any feedback is more than welcome. My most important concern is the key relationships ...
1
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0
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224
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Fashion Show ERD
working on a class project.
Have to make a ERD for a fashion show.
Not looking for a super in depth ERD, but one that will give a good grade.
I'd like it to be able to
Have a 'Clock-In/Clock-Out ...
0
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1
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41
views
What is the correct usage of IN and ORDER BY keywords when used in conjunction with subqueries?
ERD for my simple db design:
I want to order children based on their parent's last name. I am trying to use the following query:
SELECT *
FROM children
WHERE parent_id IN (SELECT parent_id
...
- 127
0
votes
2
answers
76
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Database Design for non-profit family assistance
I have a very basic ERD created for a simple database that stores some information about refuge families being helped out by a non-profit that helps provides some basic needs.
ID is the primary key ...
- 127
0
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1
answer
167
views
How should one design a logical data model for a social platform, or skip it?
After studying from 'Usage-Driven Database Design: From Logical Data Modeling Through Physical Schema Definition'a book by George Tillmann.
I want to create a logical model for a my own social ...
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1
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2k
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How to design a complex multi approval expense db schema in MySQL
I'm very beginner in database design and had the following problem to solve.
DB schema design for an expense approval system with these cases
approval system, every company has 1 or many teams where ...
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2
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2
answers
1k
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Primary keys due to inheritance
I am trying to design a database for postgrad office and we have a parent class "User" that has a username as a primary key for authentication and we have corresponding subclasses "...
0
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1
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494
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Entity-relationship for database design
Customers have the option to not provide a review or leave as many reviews as they want, but they cant have multiple reviews for the same product. How do I model this?
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1
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55
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How to re-design my relational model if there will be NULLs in one column?
I'm trying to build database which allow me store job postings from scraped websites and now I'm in phase of creating a relational model. Getting straight to the point I want to know how should I re-...
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1
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95
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Do I need to implement id column to table if i know that every added row will be unique? [duplicate]
I want to create database which allow me to store IT job offers from various websites. While creating ER diagram I started wondering if I really need an id column in one particular table. Look at this ...
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1
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291
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ERD for yearly budget ceiling advice
I'm working on webdev that involving yearly budget ceiling, but I can't wrap my head around to design such budget ceiling (my first project involving budgeting). So I need some advice.
So the scenario ...
1
vote
1
answer
378
views
ER-Model to relational mapping
"Fundamentals of Database Systems" by Ramez Elmasri covers this topic extensively, I've gone through it and seemingly the rules mentioned aim at converting the ER-Model to a relational ...
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1
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658
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Can a foreign key be used for two primary keys?
I'm still a beginner in sql and I have to transform this relation between clients and addresses and vendors and adresses. This uses 2 primary keys(1 for the vendors and 1 for the clients). My question ...
0
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1
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275
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Is the database design alright? And I'm quite lost with the admin entity here
A quick description of my system would be: there are 2 users: users and admin.
User registers on the website. Upon registration, the system will generate a QR code for the user. The user then goes to ...
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0
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0
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690
views
Is my ER Diagram correct according this business rules?
Tiny Hospital keeps information on patients and hospital rooms. The system assigns each patient a patient ID number. In addition, the patient’s last name, first name, date of birth, and date of ...
2
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1
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48
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Question on EDR: a plant may have one or more harvesting seasons
I working on the following ERD, trying to understand what is the best way to connect the entities in the example of plants! For now I'm just focusing on the right side of the ERD (yellow, orange, ...
0
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2
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271
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I'm trying to create a database for a hotel company with multiple hotels. I'm stuck on how to reserve a room?
I'm using Xampp phpmyadmin for the first time...
So I've got the basics of the database. Customers, hotels, rooms etc.
The customer can chose a check-in and check-out date.
An admin can class a date ...
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1
vote
1
answer
299
views
Where to start learning the IDEF1X method of model notation?
I recently started learning about data modeling.
After seeing @MDCCL's diagrams and thoughtful approach here, I'm interested in learning more about IDEF1X. I don't want to pay $200+ for the ISO ...
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0
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2
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3k
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How to model weak entity in ER diagram?
I was going through the weak entity concepts and was trying to model the relation Hotel has many rooms. I have come up with the partial solution presented below but i'm having a problem to uniquely ...
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1
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50
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What will be the relation between Employees and Players, given that some players are also Employees?
I have a requirement where I need to store information on Employees in a company that owns(?) a sports team and also store information on Players from other teams that are not Employees of this ...
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1
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620
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Designing User & its Sub User Database Diagram Problem [duplicate]
There are some business category e.g. Travel Agency, Hotel, Car Rental etc.
Roles:
Management rolesSuper Admin, Staff
Customer side roles are Owner, admin and sales counter
May be etc. customer side ...
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1
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216
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B2B application: users has its own users
B2B Scenario I am trying is that:
The following Roles exists in the system:
Super Admin
Super Admin Staff
Owner (client)
Admin (owner i.e. client and creates admin to define sales counters)
Sales ...
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-1
votes
1
answer
272
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ER Diagram Design
I need Help in making ER diagram that i made a ER diagram of each seperate or making it combine I made it seprate as image attached but how to combine and make it one ER diagram.
Module – 1: User ...
0
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1
answer
60
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Non-product invoice items
I am having difficulty representing additional charges in an invoice. I understand how to represent the association between an invoice and individual items in that invoice with the use of a ...
- 103
1
vote
2
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455
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Anonymous and Public User Table Design in twitter like application
I have schema design problem which I am not 100% sure if my assumptions are correct.
So the requirements are:
I need to have 2 different type of user, anonymous and public.
A user can have both ...
- 113
1
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2
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529
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MySQL - Many to Many relationship, or one to many with additional columns
Our product contains some constraints that made us contemplate which table design will yield the best performance.
Our model:
Question table which contains fields like id, body, difficulty, and tags.
...
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