Questions tagged [database-diagrams]

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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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1answer
21 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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0answers
10 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
30 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, ...
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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 ...
3
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1answer
34 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
3k 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 ...
2
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2answers
53 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
39 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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1answer
185 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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1answer
184 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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0answers
51 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
98 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
205 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
7k 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
54 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
123 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, ...
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2answers
8k 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
98 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
1k 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
27 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 ...
2
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2answers
85 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. ...
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1answer
38 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 ...
3
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1answer
14k 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
14k 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
54 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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0answers
22 views

Relationship constrains in EER

When designing a EER diagram, how do you state or show a specific relationship constraint between entities (or can this even be done). We have a relationship between two entities E and F, but for a ...
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0answers
147 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 ...
1
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1answer
785 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
3k 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
363 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
166 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). ...
4
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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 ...
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0answers
178 views

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 ...
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0answers
54 views

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 ...
2
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1answer
52 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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4answers
2k views

Is it critical for a database to have a relationship table/diagram or not?

Got a question and wanted to get the best practices or thoughts on this. I have an application that was developed with a SQL Server back end (site is Entity framework, vb.net, asp.net). The original ...
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1answer
1k views

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") ...
3
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0answers
33 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 ...
3
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1answer
1k views

Learning to draw entity-relationship diagram for a scenario involving Offices, Employees and Projects

I am trying to learn entity-relationship diagram, following question is the objective. Information consulting firm has number of offices with employees. The employees can move offices depend on the ...
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2answers
893 views

What are the bad design points in the following (simple) Entity-Relationship Diagram?

The objective is to design an Entity-Relationship Diagram for a company that has addresses, telephones, emails and representants. Here's the list of the constraints: a company has one or more ...
2
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0answers
94 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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0answers
29 views

PostgreSQL table relationship clarification

I am in the process of setting up table relationships, using a relational diagram provided by our vendor, in PostgreSQL 9.5.3 and am seeking clarification on how to relate a child table that serves ...
2
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1answer
682 views

Do you know if this are examples of non-identifying or identifying relationships?

Im using MySQLWorkbench to model a diagram. But Im with some doubts about identifying and non-identifying relationships. It seems that all relationships of the project are identifying. For example, a ...
4
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2answers
230 views

Can relationships have relationships?

I have the following requirements (as part of a larger system). In the database, I need to maintain a list of parts, suppliers who sell those parts. Many suppliers can sell the same part and each ...
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2answers
106 views

Nullable Fields to Separate Table?

My website has a form page that has radio buttons yes|no corresponding to 7 questions. When the user selects yes, the user needs to specify a value (either a location, name, or medical condition, ...
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2answers
56 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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1answer
25 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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1answer
1k views

MySQL WorkBench SQL : Cannot Add Foreign Key Constraint (Error 1215) while creating database

Problem: I am receiving the Error 1215: Cannot add foreign key constraint error while running my MySQL schema code generated from the EER Diagram I used to model my database. The Error occurs ...