Questions tagged [database-diagrams]
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155 questions
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In an ER diagram, can an entity know information about a non-directly connected entity?
Imagine a simple database like this:
[credit card] --- has --- [customer] --- places --- [order]
Of course the order would know which customer placed it, but would it know which credit card the ...
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Confusion regarding Weak and Strong Entity types!
Apologies if this is a trivial question, I recently started studying about E.R. Model. Let me try to clarify my doubt using an example. Consider the two entities,Customer and Loan in a relationship ...
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Ternary relationship in ER diagram
From a text description I have to draw the ER diagram of a database for blood donation department of a hospital. I struggle to illustrate one information:
"A patient receives blood from a ...
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MySql: Ecommerce product variant structure
I have a problem with the database organization for ecommerce product variations. Googling, I found a lot of articles and every article says that if the product has more variations, it should be in a ...
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Is this small business database design on the right path?
I am designing a database for a small business that would like to use this system for a very long time, meaning they expect to maintain and grow the system but they want to start off well. This is ...
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Can an entity appear more than once on an EER diagram?
I am modeling a database that is a bit complex, and I am having some issues to draw a clean diagram representation of it. Especifically, there is an entity "A" that is a part of many ...
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Model availability for house rental database (AirBnB like)
I'm designing an house rental application database and I'd like to model the concept of availability for rooms. I'm still in the early phases of development so I'm thinking in terms of entity-...
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Should I put the attribute in each table even if they are linked to increase performance?
Creating a schema for a workout app, currently building the logs for finished workout sessions.
Here's the part I'm wondering about:
Wondering if I should put date in each table. The reason is that I ...
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MySQL gives Unknown column error when forward engineering database from diagram
I have a MySQL EER diagram the I forward engineer into a database. I also use the forward engineer feature to generate insert statements for data automatically. After entering about 120 rows of data I ...
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209
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Should I include a junction table with a primary key in my ski rental database schema?
I need to make the ER diagram and the relational schema of the Ski rentals. I have an Customer, Rental and Ski as a entities as well as their attributes. Customers and Rentals should have the one-to-...
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Database Dependency Chart?
I have several SQL Server (2008 forward) and Oracle (12c forward) legacy databases running on a server... I know for a fact that various stored procedures point to other databases, like select * from ...
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Is my food-tracker's database designed properly? (ER diagram + SQL Relations)
My idea:
The database will store foods, days, and "inserted foods" aka diet_logs (days and diet_logs have both existence dependency)
for each diet_log of a specific day, I will create a ...
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Football/Soccer club entity-relationship diagram. Is there anything wrong or that can be improved?
I want to create a db to store my soccer/football team (Xerez) data. I have made an entity-relationship diagram (with no cardinalities), but I am wondering if it is correct.
This is the diagram:
Next,...
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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 ...
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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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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 ...
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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 ...
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Database Design For Realty Website Review
I am designing a real estate website and wanted feedback from some professionals about the database schema that I came up with.
I created a property table that would have each house. Each house can be ...
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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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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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what is best way to handle history tables in postgresql?
I am working on the following database structure/diagram for an app using postgresql 13 server
Is there a better way to design these table relationships with the tables subscriptions_history and ...
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How do I produce the relationship diagram in Microsoft Sql Server?
How do I produce the relationship diagram in Microsoft Sql Server?
Here is a visual of what I am talking about here:
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Question for my entity relationships
I'm not sure how I should think regarding my database design. I have made this database schema below. And I'm trying to think about the relationship between the entities. I have read through online ...
user236562
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DB relationships with historical tables review
Idea is simple. User -> Projects -> Sprints -> Tasks, but I need to keep historical versions for them. It will fit to my requirements or there are some changes to be applied? - or different ...
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Database ER diagram review. Is this a good database design ? [HELP]
This database For school management system.
Please review and help me with your ideas.
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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
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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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Is Star/Snowflake database design good for applications? What is the alternative?
I need to solve an exercise for a pharmaceutical company, they ask me to create a database structure from scratch given a few informations.
Because I want it to be scalable and "future proof"...
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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 ...
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744
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Table Diagram and Access File of Contact Database for Church
I have volunteered to design and develop an MS Access database for contacts at my local church in Jamaica, which has no budget to hire a database expert. I have attempted to design a database for the ...
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ER Diagram | Group, Post, User relationship
I need to design an ER diagram, but I am confused in a section, more specifically how to relate the post with the groups, because I need that post contains the information of in which group I publish ...
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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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How is this E-R diagram of an identifying relationship's mapping cardinality correct?
According to textbook Database System Concepts,"The identifying relationship is many-to-one from the weak entity set to the identifying entity set, and the participation of the weak entity set in ...
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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 ...
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Database ER diagram review. Is this a good database design?
I have a task to design an ER diagram and task is given as points below is the description of the problem:
A telecommunications company employs thousands of consultants.
Each consultant is assigned ...
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How can I create a database diagram, showing clearly the FK and PK in SQL Studio 2016?
I would like to know the best way to create a database structure diagram, that shows relationships between certain tables. I am using SSMS 2016.
I tried using "database diagram" option in the SSMS ...
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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 ...
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Carry forwarding token wallet concept [closed]
I'm trying to create a carry-forward wallet system.
Recharge part
I'm developing an app that has the carry forwarding token wallet concept. However, when an user recharge their wallet, an amount of ...
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Database diagram for linked server tables
I run Microsoft SQL Server Express 64-bit version 14.0.2027.2 (X64) on Windows 10 Pro 10.
I created a linked server connecting tables from a Microsoft Access (mdb) database to Server Objects/Linked ...
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ER Diagram Design: Should every entity have a primary key? And can we have sub entity? [closed]
Problem: Design a ER diagram such as:
An item has the attribute: description.
An item can be sold by a company or a person.
A person has the attributes: name, phone and email.
A company has the ...
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The best practice for SQL + NoSQL database design [closed]
I’m in process of designing database architecture for my diploma project and I have second thoughts about different solutions.
I know and understand all my objectives can be done within relational ...
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Is it possible to generate DB diagram for all SQL databases opened in SSMS
At the present we have to go to each database and manually generate database diagrams, so I want a way to automate this.
Question: Is it possible to generate DB diagram for all SQL databases opened ...
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PostgreSQL Schema Builder/Diagrams [closed]
I have worked with PostgreSQL, primarily using the Django ORM (started with MySQL and migrated to PostgreSQL) and using pgAdmin for maintenance tasks.
I am now working on an open source project ...
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Can I show a relation - "Either in this table or in that " in ER diagram?
I am making a database for handling leave applications in an academic institute. Given that there is hierarchy existent in such institutes, and I need to keep record of the people that were at these ...
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Entity Relationship Diagram - Entity depending on attribute
I have an ER-Diagram containing the entity employees. When employees have high skills they may supervise lower skilled employees. How can I model that in an ER-Diagram?
My initial approach of was to ...
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Need help to design ER diagram
I need to design an ER diagram for a centralized healthcare management system for my college mini-project.
Firstly, I came up with the following ER diagram.
ER-diagram-1
While designing the tables ...
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Variable layers of data in a multi-country addresses system
My diagram
I want to record addresses in my database. The layout I have right now is visible in the diagram below:
Considerations
Continent, Country, Subdivision and City will be pre-filled, Address ...
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Setting up relationships on a gaming schema with multiple locales
I've devised the following schema:
Where BotLocale holds locales like en-US, es-AR, etc. GameArtifact has a primary key which is artifact_id and GameClass with locale, identifier being the primary ...
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Room bookings database - does it make sense to create two tables instead of one column?
There are two types of entities: user and room. A user can
book room
select room
unbook room
unselect room
"Selected room" is a state that indicates when a user has decided to book a room and so he/...
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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 ...
