All Questions
Tagged with erd database-diagrams
59 questions
1
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356
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Can I illustrate how a relationship depends on another in an ER diagram?
I'm new to data modelling and trying to build my first ER diagram for supermarket management. My current diagram is based on the following description which I myself come up with:
"Suppliers ...
- 11
1
vote
1
answer
981
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Chen notation to crow's foot
How do I illustrate relationships which has an attribute in chen notation to crows foot notation?
Example:
There is an attribute "quantity" in the relation. How do I draw that in crow's ...
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0
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0
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983
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
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0
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1k
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Entity relation with itself
I want to make an ER diagram for scientific research papers, one of the constraints is that a paper shouldn't cite itself.
I'm not very sure how to achieve this, as this question points out, the ER ...
0
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1
answer
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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0
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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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0
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1
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291
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How can I categorize entites by their age in an entity relational diagram?
I am designing an entity relational diagram and I need to categorize entities in groups by their age.
What I have is an entity of Person and some personal attributes about it. But I want to have ...
user226621
0
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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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0
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1
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7k
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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
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1
answer
19k
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How do I represent foreign key in an Extended ER Model in Chen notation?
This is a spin-off of the question at How to represent foreign key in an ER diagram? which is too vague about the needed notation.
There the idea of underlining FKs with a dotted line is stated. I ...
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2
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1
answer
8k
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Chat/conversation history, entity relationship diagram
Totally aware that there are very similar questions, went through each of them, but those are pretty simple/basic solutions from where i took some things and ideas to create below entity relationship ...
- 123
1
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1
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4k
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What is the Relationship between Instagram users and user followers
I'm building a blog project, which each user can follow other users. I'm still figuring out the design and creating the diagrams first. I know that the relationship between users and followers is many ...
- 125
2
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2
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797
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How to Represent Equation with Variables in Relational Database
I am building an application to store the different formulas used for different subjects in school, and I have drawn the following database diagram to depict that scenario:
I am having trouble ...
12
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3
answers
14k
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What do the entity-relationship diagram (ERD) symbols used in DBeaver mean?
I don't understand the ERDs used by DBeaver. The diamonds and dots at the ends of the line arent the crow's foot I'm used to. I've googled the subject and checked the docs but can't find a straight-...
- 498
2
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0
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6k
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Crow's foot notation--what is the difference between "one" and "one-and-only-one" regarding relationship cardinalities?
I'm trying to figure out the difference between the single-bar and double-bar cardinality indicators as in the figure below:
Some sources seem to use one notation while others use the other. I can't ...
- 179
1
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1
answer
2k
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How to create a correct entity-relationship diagram (ERD) about a video game profits scenario
I'm starting to build my application database, and I'm really new to the this world, so I have a lot of doubts about my ERD and if its entity types and relationships are ok.
This is an application ...
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0
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1
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174
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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
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2
answers
2k
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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
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0
answers
2k
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Gaming shop database schema
I'm trying to design schema for my personal project that would be an online gaming shop. I would like to ask you guys for any suggestions/tips on how could I maybe improve my current draft.
Concerns:
...
- 29
2
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0
answers
330
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Modelling a database for a simple IT device tracking scenario
Sorry, my English is not that good.
I need a simple IT device tracking sytem at work.
For each device I need to know its current location, status and ownership (employee to which it is assigned).
...
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1
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0
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705
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Modelling an entity-relationship diagram for a scenario involving companies, services, and clients
I am creating an entity-relationship diagram (ERD) for managing workflow and other details of Company X in which I am maintaining details of the following objects:
Employees of Company X
Services ...
- 11
1
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0
answers
175
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Creating an entity-relationship diagram about an art fairs and galleries business environment
Scenario description
The charactheristics of the business domain under consideration are:
Each and every art item has a unique identifying number, and also a name and asking price.
Art galleries ...
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1
vote
1
answer
48
views
How to express a "some of which are" and "not all are" relationship with enhanced entity-relationship diagrams?
For example:
Gardens have attribute gate, Condos have attribute door. Some of the Gardens and Condos are Private_Properties. On the other hand, Private_Properties are not restricted to only Gardens ...
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1
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0
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419
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Basic ERD analysis for a martial arts business domain
I am working on a basic website in order to support querying results from martial arts tournament data. We use participation data to determine things like who gets to host tournaments, regional awards,...
- 159
3
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0
answers
217
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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
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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
1
vote
1
answer
3k
views
Modeling an entity-relationship diagram about Clients, Orders, Payments and Bills
There is a part of an entity-relationship diagram creation that troubles me, I don't know if it's ok. I tried to follow these instructions:
A client makes an order (which has products).
When the ...
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2
votes
3
answers
4k
views
How to interpret ternary relationship?
I have tried to search online on how to interpret these ternary relationships but haven't found any clear answer. Since I don't understand how to interpret it I am having trouble changing it into ...
- 145
1
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1
answer
979
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Modeling a Recursive Association for Linking an Entity Type to Itself
I am designing a simple database as follows:
The database should contains an evolving set of standards;
each standard has a library of controls;
A single control in each standard may map to one or ...
0
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2
answers
464
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Entity-Relationship Conceptual Data Model [closed]
So I am busy learning databases for an rpg I have been thinking of to learn more specialized techniques with game development itself. Now I am trying to draw a conceptual data model to get things ...
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6
votes
1
answer
2k
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Postgres 9.6 export the database structure as pdf [closed]
Is there any tool/software the can export all the tables structure (column names , its datatype ) in the database as a pdf/excel/word. additional diagram export will be added advantage.
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2
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0
answers
127
views
How can you use an entity-relationship diagram to document business processes?
Past exam question: How can you use an entity relationship diagram to document business processes?
As far as I know, I would use an entity-relationship diagram (ERD) to document the relationships ...
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5
votes
2
answers
1k
views
How can I represent the entity types depicted in an ERD as relations with attribute names?
I have created the entity-relationship diagram (ERD) shown below (for brevity, each individual bubble-shaped box portrays multiple attributes):
Considering such an ERD, I have to convert each entity ...
- 253
7
votes
1
answer
2k
views
How to model a Letter Transportation business context in a database diagram?
I am trying to crate entity-relationship diagram for a transport company database. This database should store information about letters, deliveries, moving letters from one warehouse to another, and ...
- 173
3
votes
1
answer
1k
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Ternary Relationship or (n-ary)
I'm trying to find the difference in terms of modeling a ternary relationship v/s a binary relationship in the following case. Any piece of advise would help me a lot.
Company has editors who are ...
2
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0
answers
727
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What is the difference between (Superclass/Subclass) Total and Partial Specialization?
What is the difference between total and partial specialization of superclass/subclass (or supertype-subtype) structures in enhanced entity-relationship modeling?
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3
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0
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2k
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ERD for a Contract between a Writer and a Publisher: Is it correct, can it be simpler?
I created an entity-relationship diagram (ERD) for a book publishing business context that I will detail bellow.
Entity types
The entity types of interest are:
Writer
Work (as a book)
Publisher
Split ...
- 141
2
votes
1
answer
134
views
Can someone please tell me where I went wrong for an exercise submission?
I recently submitted an assignment in a group for our databases class and we lost points on one of the exercises and the correction is unclear. If someone could examine the question, the submission ...
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5
votes
3
answers
12k
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How do I read ERD Notation (crow's feet) to convert to Natural Language?
Background
I am attempting to insure I understand how to read ERD (Entity Relationship Diagram) notation so I can convert it to a natural language explanation.
I'm trying to insure I can explain a ...
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5
votes
1
answer
3k
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ERD for a web development company
I am working on an ERD which represents the relationships between entities in a Web development company behavioral model.
There I have entities like:
Customer
Service ----------- (like: web ...
- 157
1
vote
0
answers
187
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ERD Diagram based on Crow's Foot model for Milky Way Jewelry
this was on my final exam this past winter exam season, in search for the answer since i got it wrong:
Draw an ERD diagram based on the Crow's Foot model for a database to support the basic ...
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4
votes
1
answer
2k
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Modeling Subclass (or Subtype) Constraints in an Entity-Relationship Diagram
Scenario description
Can someone help me out on how to model the situation that follows:
There is a superclass (or supertype) called PRODUCTS, which has the subclasses (or subtypes) named FOOD and ...
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2
votes
2
answers
26k
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What does the Union sign in EER diagrams mean?
I know disjoint and overlapping, but what does the union like sign mean in an enhanced entity-relationship (EER) diagram...? For example:
In other words, what does this diagram mean?
- 415
3
votes
1
answer
10k
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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 ...
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4
votes
1
answer
1k
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Do I relate entities that are indirectly related when creating a student-course ERD?
I'm trying to create an ERD for a tutor center, this is what I understood from their operations:
There is the tutor center director, then under her there are sections/departments. It, math/calculus, ...
- 41
5
votes
1
answer
2k
views
How to model an “is a” relationship in an ERD using Crow’s foot notation?
I have to create an entity-relationship diagram (ERD) for an assignment. I am doing this in a particular drawing tool with the Crow’s Foot notation. There is however one thing I cannot figure out:
...
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15
votes
3
answers
9k
views
Modeling a scenario in which each Music Artist is either a Group or a Solo Performer
I have to design an entity-relationship diagram (ERD) for a business context that involves the delineation of music artists, as I will detail below.
Scenario description
An Artist has a Name, and ...
- 151
3
votes
3
answers
4k
views
Database design: 4 types of users but have different functionality , separate or one table?
I have 4 types of users:
Admins , normal user , company , service provider
Admins and normal user share some attributes (id .first name ,last name ,phone ,mail) company and service provider share ...
- 31
0
votes
1
answer
2k
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Cyclic relationships in ER Diagrams
I am trying to draw an generic entity-relationship diagram (ERD) to model a software object (Let's say a XML file). This XML file has references to other XML files. Also, if a XML file (say "file-A") ...
- 103
1
vote
1
answer
3k
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How much the decision to use ternary or binary relationship influences the accuracy of the model with regards to a given business model?
The question title is very long, so here's a little bit of context to (try to) make it clear.
I asked a question regarding ternary relationship. The question was Ternary relationship: what's the ...
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