Questions tagged [database-diagrams]

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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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1answer
2k views

I Need Help With My Database Design for Product Management

I'm designing a MySQL database and the front end for my work. The database will store all of the products that we sell on our marketplaces and their relevant data. We will be able to lookup products ...
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3answers
4k views

Crow's Foot notation and identifying -vs- non-identifying relationships

Is it possible to distinguish between identifying and non-identifying relationships using the Crow's Foot notation? Case in point: In table Book, part of the book's Primary Key is a FK to the Author ...
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1answer
35 views

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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1answer
36 views

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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1answer
137 views

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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18 views

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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1answer
27 views

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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0answers
21 views

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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1answer
185 views

ER Diagram about Music Online Store

I am attempting to make an ER diagram where the customer buys music online. We were just in the first weeks of tackling database so a lot of topics isn't introduced yet. Here's what I've done so far: ...
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20 views

Strong Relationship Confusion on ER Diagram

In this ER diagram, there's a dashed line between the DAMAGE and RENT entities, signifying a weak relationship. But, as I understand, a weak relationship exists where one entity does not contain a ...
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1answer
401 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 ...
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2answers
89 views

payment table in relational datase

I have to model a database table for payments. These need to have two fields payment from and payment to and this needs to link to two tables one is clientA and clientB as in the representation below. ...
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2answers
1k views

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-...
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1answer
33 views

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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1answer
57 views

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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3answers
2k 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 ...
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1answer
2k views

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 ...
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1answer
31 views

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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0answers
123 views

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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1answer
61 views

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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1answer
40 views

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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1answer
36 views

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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52 views

2 Relationships between same 2 entities

New database student here. I am having troubles understanding this case for ER to relational database conversion. So when mapping this to a database does the table for entity one look like this? ...
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0answers
54 views

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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1answer
38 views

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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2answers
86 views

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 ...
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0answers
46 views

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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1answer
30 views

Replacing the removed database diagrams feature [closed]

I have a SQL Server database and want to create an ER diagram for it, to analyze tables and relationships. The option to create a diagram is no longer present in SSMS 18. Is there any free tool ...
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0answers
89 views

Modelling Orders and Messages for an e-Commerce database

In my e-commerce application I would like that buyers and sellers interact via a messaging system to purchase products. The process consists of: The buyer inquiring for a product The seller responds ...
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1answer
687 views

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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0answers
1k views

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 ...
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2answers
9k views

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?
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2answers
181 views

Error 1005 when Forward Engineering EER diagram

I have created an EER diagram (as shown in the image bellow) in MySQL Workbench and wanted to Forward Engineer to build the DB. After configuring the model options to the Target MySQL Version and ...
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1answer
435 views

Modelling products along with their attributes and discounts for an e-Commerce database

Scenario My application will have products belonging to 1 company. Each of those products will: Have at least 1 quantity Have 0 or more discounts Have 1 or more attributes Belong to 1 category, which ...
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2answers
10k views

What is the best way to create a database diagram for SQL Azure without having to install SQL Server?

I have a database on SQL Azure and want to create a database diagram for that, but don't want to have to install SQL server and copy the database etc. Is there any way that I can do it that anyone ...
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1answer
114 views

SQL Server Database Diagram

I am using SSMS v18, I need to create an ER diagram from my database. As Microsoft removed diagram from new version of SSMS (v18) so now How can I get a diagram for my database??
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1answer
2k views

Is it possible to change the color of relationship lines in MySQL Workbench diagrams?

I have MySQL Workbench Community Edition 8.0.15 installed on my Mac OS 10.14.3. I'm currently working on making an ERD with Workbench's EER Diagram. My problem is that whenever I export my diagram, ...
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1answer
28 views

Is there a place to store ERDs in Postgres?

Is there a designated spot in Postgres to store Entity-Relationship Diagrams (ERDs)? I could just create a table with a BTYEA column or something, but I want to make sure to use what exists if ...
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2answers
211 views

Does the relationship between teams and matches have a many-to-many cardinality ratio?

Diagram I created the following diagram: Considerations So I will create two tables, one called Match and the other one called Teams. In Match there will be data about two teams, Away and Home. Let ...
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1answer
39 views

How to avoid losing information via UPDATEs due to database design issues

Business requirements I have a database where information about documents and their related packages are kept. Each document can have multiple packages, and each package has its details and product ...
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1answer
15k views

Number of ISA relationship triangles in an Entity-Relationship Diagram

The following two diagrams are nearly identical. However, in one, there are two ISA triangles from the Entity "Movie" and in the other there is just one. What is the difference in meaning?
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5answers
15k views

Automatically create ER diagram from database schema

I have a database with 193 tables and I need to create an entity-relationship diagram from them. There are no formal relationships between the tables with respect to FKs. The relationships are mapped ...
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1answer
62 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 ...
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186 views

Multiple tables for different types of transactions?

Considering a trading system as an example. Would it make sense to have two different tables for credit transactions and asset transactions? creditTrans : table id userId transType status amount ...
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1answer
1k views

How do I change where database diagram relationship lines attach in MySQL Workbench?

Sometimes, MySQL Workbench makes some strange choices about where table relationship lines get attached. For example, two vertical lines would be better in the following: For a while, these boxes (...
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3answers
4k views

I can't save Database Diagrams

I'm trying to save a database diagram but I'm getting an error. How can I fix this? Cannot insert the value NULL into column 'diagram_id', table 'SOFT.dbo.sysdiagrams'; column does not allow ...
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0answers
568 views

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: ...
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0answers
199 views

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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1answer
7k views

Database design for an exam system

I am working on creating a simple exam system, in which you are going to be basically able to store students, classes, exams, questions and scores(and some other stuff that those depend on). I am also ...