All Questions
42 questions
0
votes
1
answer
30
views
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 ...
1
vote
1
answer
290
views
How to count the number of relationships to a table in MySQL?
I am arranging an ERD diagram of an existing database with about a 100 tables, to add some structure to the process, how rank out the number of relations the tables have to each other?
For example, ...
- 135
0
votes
0
answers
157
views
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
vote
0
answers
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
0
votes
0
answers
981
views
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 ...
0
votes
1
answer
2k
views
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 ...
- 59
1
vote
0
answers
157
views
ERD related, can you make one to one relationship with a single attribute entity to another entity?
ERD Here
So for my database project, I designed a meat supply chain optimization project for a large organization, for example such as walmart, where every part of the chain is owned by the ...
- 11
1
vote
2
answers
455
views
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
vote
2
answers
529
views
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.
...
- 111
0
votes
1
answer
7k
views
Is my way of creating a entity relationship diagram correct?
From what I understand, 1)table customer and table order should have a one to many relationship since customer has orders. 2)table order and table payment should have a one to many relationship since ...
-1
votes
1
answer
1k
views
ER diagram to Relational Schema (Many to Many relationship)
In this ER diagram, can anyone explain how we should convert the many to many relationships ('view', 'update' and 'diagnose') to Relational Schema and then SQL? What I think is that there shouldn't be ...
0
votes
1
answer
174
views
Creating and querying a database to set hierarchical associations between Groups, Users, Items and Points
I am working with three entity types, Group, User and Item. A Group consists of Users, and a User consists of Items.
Now, I have to work with a fourth entity type: Point. I want to be able to ...
- 103
0
votes
0
answers
2k
views
Creating a Database for Multiple Calendars Support
I am trying to create a calendar application that can support multiple calendars, for instance Indian, Nepali, Russian etc. Users can enable or disable the calendars according to their needs.
I have ...
0
votes
2
answers
154
views
Modelling two dependent many-to-many relationships
I have a user who may have 0 or more foo's and bar's. Here is a diagram:
Each foo has a unique integer ord.
If a user has a bar, then this implies that he has a foo with ord=1. A user may not have ...
- 137
0
votes
2
answers
2k
views
How to maintain customer addresses for Orders?
The database I am designing is part of a project I am working on. I have come up with 3 simple "business rules":
Customers must either be Individuals or Businesses (a business belongs to a certain ...
- 109
1
vote
1
answer
107
views
How to make Event (like a Party) Sources mutually exclusive?
I'm designing an entity-relationship diagram (ERD) for a marketplace of events. An event can be created by a user, in which case the Event table must have owner_id or we pull it from an API in which ...
- 11
3
votes
0
answers
217
views
How to design a database for my entity-relationship diagram about Projects, Tasks and Developers
I'm new to database and my entity-relationship diagram is as follows:
According to that I designed my SQL-DDL database statements as shown below:
CREATE TABLE Developer (
DeveloperID int NOT ...
- 131
1
vote
1
answer
5k
views
Feedback on an entity-relationship diagram for a movie theater business domain
I have an assignment due next week, and for that assignment I am supposed to learn MySQL and create an entity-relationship diagram (ERD).
My current attempt
Now I've made this ERD
The issue
I ...
Basel Noeman
0
votes
1
answer
12k
views
How do we express a weak entity to be dependent on another weak entity?
Perhaps I am looking at my entities as a hierarchy rather than a set of relationships; for sake of an example I have three tables:
Authors
Books
Content
Where Authors writes Books and Books contain ...
2
votes
0
answers
1k
views
A Shop can have Products from a Supplier
I'm creating a Platform where Suppliers have Products that Shops can choose, add to their Shop and start selling.
My situation is as follows:
A Supplier can have many Products (for example: 'T-...
- 169
0
votes
1
answer
677
views
how to get a schematic diagram/layout of the an existing database
I am looking for a schematic diagram of an existing database.
More precisely, I wan't to re-create the database model / schematics / the Entity Relationship Diagram (ERD) showing all the links between ...
- 105
0
votes
1
answer
4k
views
Making an ERD of a movie database
I have a school project in which I have to design a database and my theme is Movie database of sorts. I created a basic ER diagram and I will post a picture here so you can tell me where are my ...
- 101
8
votes
3
answers
8k
views
Which one is an ER diagram?
I have started to study ER diagrams. When I browse through the ER diagram tutorials, I found something like figure 1:
Figure 1
I tried to create a sample ER Diagram in MySQL Workbench like:
Figure 2
...
- 183
1
vote
1
answer
129
views
How can I better model the relationships in this project?
I'm developing an internal tool (as an intern). We deal with a lot of hardware, which is all custom and managers have a hard time knowing who is developing on what machine.
The three main things to ...
- 11
2
votes
0
answers
2k
views
What is a good database design approach for my Online Quiz Android Application?
I have been working on an Android Online Quiz Application with PHP & MySQL. I know what attributes i need however when designing the relationship it becomes complex and confusing when I analysed ...
- 121
5
votes
2
answers
5k
views
Dog Adoption Database Design
Apologies if this isn't the norm, but I am seeking advice for the database design for 'dog rescue/adoption'.
I've done my normalization research and this is my first attempt at database design. Any ...
2
votes
1
answer
211
views
Is this table in my ERD redundant? (Image)
I am developing a research article database for a project. My professor approved this design but I feel like the Author's_University table is redundant and that University_ID could just be added to ...
- 45
3
votes
1
answer
10k
views
Representing a Superclass/Subclass (or Supertype-Subtype) relationship in a MySQL Workbench diagram
Situation
I am trying to figure out how to represent a one-to-one (1:1) relationship regarding a superclass/subclass or supertype-subtype structure in an entity-relationship diagram (ERD) of the kind ...
- 33
1
vote
0
answers
2k
views
Quotation and invoice mysql table
I am trying to develop a small business web application for my friends business. I do have some php,html experience so I have done the interface and all. Now I am trying to work on the database. The ...
- 11
0
votes
1
answer
2k
views
Does my ERD look well designed?
I am making a database at no cost for a local dance school. I'm still very new this would like to be sure that I designed it appropriately.
From the front end, the parent will: fill out their ...
- 115
-1
votes
1
answer
382
views
How to create a SELECT statement involving a subtype
Okay, so all I'm trying to do here is "list" the managers who supervised the employee that charged a customer $100 for a rental on November 1st, 1998.
My issue is that I don't know how to select the ...
0
votes
1
answer
64
views
Relationship issue
I'm working on a ERD with mysql workbench, and i have a little question.
I have a Database with this tables:
company_address
country
state
city
I want to store the address of the company with all ...
- 101
1
vote
1
answer
72
views
Financial Inst - Model Role+Relationships b/w Person and Account
A Person can be on one-or-more Accounts. For each Account a Person is on, Person has a certain role on that account i.e.
Person 1 is primary on Account 1
Person 1 is joint on Account 2
Person 1 is ...
- 113
1
vote
1
answer
6k
views
Cannot Add Foreign Key Constraint
Can anyone tell me why there are errors such as:
Cannot Add Foreign Key Constraint
And am I on the right track?
My schema looks like this:
DDL:
DROP DATABASE technology_university_hospital;
...
- 111
3
votes
2
answers
3k
views
Should I use a three-way associative table?
I have a scenario which I believe I have come up with a solution - however, I can't be sure it's a manageable one, or even correct. The scenario is as follows.
There are are three tables involved in ...
- 41
1
vote
1
answer
221
views
Implementing a simple ERD in MySQL: is the implementation below 100% compliant with the ERD?
ERD
Consider the following ERD:
Tables
From it, I derived the following tables:
Company
------------------
c_id c_name
------------------
CompanyEmail
------------------
c_id e_id
--...
- 265
0
votes
1
answer
6k
views
Digital content eCommerce schema advice? [closed]
I don't have much experience designing databases, I'm looking for some advice on my design from more seasoned designers/developers. I'm developing a digital content eCommerce store which will be ...
1
vote
1
answer
4k
views
Advantages of "middle" tables in one-to-many relationships
Entities:
Lists
Leads
What I am trying to achieve is a scenerio where in the relationship between lists and leads the following constraint is applied: A list can have many leads, but a lead can only ...
- 113
2
votes
0
answers
1k
views
The nature of the relationship between two tables in MySQL
Good day. I'm designing a database for a research project where we're predicting whether or not young female athletes will rupture their ACL(s) based on the nature of a test jump recorded with a ...
- 123
5
votes
3
answers
2k
views
Are there any tools to go from ERD to DB design and vice versa? [closed]
I'm learning DB design and looking for some tools, preferably open source software, that could help go from an ERD to a DATABASE and vice versa.
For the record, the database i'm using is MySQL.
- 364
4
votes
2
answers
6k
views
Is my ER Diagram correct? Why use relationships?
This is the first time I've made an Entity Relationship Diagram (ERD) for database that will be built on MySQL. The business domain of relevance is about equipment issues management.
Prior to this, I ...
- 41
5
votes
3
answers
1k
views
how do I model this in database?
I am using mysql as my backend database. Here is the use case;
A HolidayPackage is configured with some default offerings. These default offerings can be up/downgraded based on the options provided. ...
- 267