Questions tagged [erd]
Entity Relationship Diagram
398 questions
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How do you open a *.pgerd file and view the database diagram?
I have a *.pgerd file that I want to open an view the database diagram. What free tools can I use? I also have access to IntellJ Ultimate Edition, so if anyone knows of plugins I can use, this would ...
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Drawing an entity-relationship diagram for a store business context
I have an entity called Users, with the attributes Id, Name, and Phone No. The objective is to develop an entity-relationship diagram (ERD for brevity) where Users might be Store Cashiers, and also ...
CommunityBot
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Understanding many-to-many ternary relationship sets
I am new to entity-relationship diagrams. I'm a bit confused when it comes to interpreting ternary relationship sets such as this:
Does this signify that every relationship instance of Party will ...
CommunityBot
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Could a Tool Like ChartDB Work for MongoDB Schema Visualization?
I’m one of the developers behind ChartDB, an open-source tool for database schema visualization, particularly useful for relational databases (RDBMS). Our tool helps users generate ER diagrams to map ...
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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.
...
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How can I model a medical scenario in an entity-relationship diagram?
I am a self-taught frontend developer that is trying to go full-stack, so I am trying to teach myself data modelling by means of working on some exercises out of a database management book.
In this ...
CommunityBot
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Can someone give me feedback on my ER diagram?
I am new to creating ER diagrams and was wondering if anyone could review one that I constructed for an assignment. I used min, max notation in my design but I am not entirely sure if I did everything ...
CommunityBot
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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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Use the following business rules to create a Crow’s Foot ERD
Is there any mistake in the ERD???? it looks weird.
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ESports League ERD
I'm creating a database for an esports league and am having some issues putting it all together for an ERD. Here's a quick rundown on how the game works:
There are 2 teams of 5 Players each. These ...
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Need help with ER diagram for my pet project
Right now, I have started to learn more about databases. One of the topics that I have more questions about is the relationships between tables. For example, I am currently trying to create an ER ...
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Please help me understand this problem about cardinality
Me and my friend are in the process of creating an ER diagram for a professional soccer league, we are both very new to Database so we aren't sure if everything we do is correct.
When creating a ...
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Create an ERD diagram from a set of SQL CREATE TABLE statements
We have a Snowflake database that does not maintain relationships between tables. The lack of relationships is not my decision and I have no control over this. I would like to generate an ERD diagram ...
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ER-Model to relational mapping
"Fundamentals of Database Systems" by Ramez Elmasri covers this topic extensively, I've gone through it and seemingly the rules mentioned aim at converting the ER-Model to a relational ...
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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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Entity-Relationship Diagrams: Identifying which way a relationship flows
I am having trouble grasping the "relationship" concept of an entity-relationship diagram. For example, you have Classroom and Furniture as your entities. If you were to put a relationship diamond ...
CommunityBot
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Chen ERD: What improvement could I make? Can relationship `RECEIVES` be omitted since entity `INVOICE` is a weak entity of `CAR`?
Assumptions:
A salesperson may sell many cars, but each car is sold by only one salesperson.
A customer may buy many cars, but each car is bought by only one customer.
A salesperson writes a single ...
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ER model of an online bookstore
By my study, I am required to create an ER model. This is the first time I have done this, and I am not sure if the connections are correct. Can you please tell me if they look correct?
Thank you in ...
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Recommended way to build database to contain users and chatgpt data
I am looking to create a Rails application to interface between users and Azure ChatGPT. I will include my ERD diagram showing a couple of options in building the database tables and table ...
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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 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 ...
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Associative relationship for "manager working term"
I am creating ERD following some database design requirements.
This specific part on the ERD is what I am trying to represent.
I made the MANAGEMENT entity because it's related to DATE_ACCEPTANCE, ...
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Should I Use a Composite Key or a Single-Column Primary Key in my Entity Relationship Diagram?
I am designing an Entity Relationship Diagram (ERD) for a database that includes a table with variants annotated by different tools. In this table, each variant is annotated by a specific tool, and ...
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When to apply normalization in database design
Prior to learning about normalization I would usually read the scenario/description in the requirements and draw up an ER diagram (using Chen's notation) using nouns as entities and verbs as clues to ...
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2nd Normal Form ERD thoughts
This ERD has completed 2nd Normal Form normalisation, as every table has a primary key, the data is atomic, there are no repeated groups, and there is no partial key dependency.
What are your thoughts?...
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ERD directly producing 5NF relational schema - is this desirable?
I have been given a case study of Event Management. I have to develop an entity-relationship diagram (ERD), and based on it check if the resulting relational schema meets the different normal forms. I ...
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pgAdmin 4 ... is not present in the table
Hello
Here is my erd and the below my creating table codes;
-- This script was generated by the ERD tool in pgAdmin 4.
-- Please log an issue at https://redmine.postgresql.org/projects/pgadmin4/...
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feedback and improvements for London Autos ERD
London Autos has several locations within London and its surroundings, from its humble beginning a decade ago in an east London garage, the business has expanded into a multi-million-pound business. ...
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in ERD of a system in which teachers evaluating other teachers of their departments how can i connect Teacher, evaluation_result entiy,
A teacher could be an evaluator and also be an evaluatee. How can I achieve this?
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Deleting a row in one table should also delete the corresponding rows in another table
I have these tables: station and water_types. The user may only have one station, and if the user wants to delete the station, the corresponding water_types must also be deleted. In a station, there ...
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Help needed with database design
I am designing a real estate database to keep records of plots (lands). There are many aspects to it like sale deeds, buyers, sellers, etc. But specifically, the bit where I've got stuck and need your ...
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ER Diagram for Missed Visits
I have to design an ERD for a hypothetical scenario. In the scenario, the nurse at a rural clinic needs to get summary data regarding patient visits so she can reschedule canceled or no-show visits.
...
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Need help with first ER diagram
This is my first time doing the diagram. My teacher isn't the best at helping out or responding to questions so I've come here to ask for further assistance. I think I've mostly got it correct, but ...
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Get ERD from my Redshift database
I am a newbie in database management/governance.
The problem: I have my companies Postgres RDB in AWS Redshift. So this is not a private project, but enterprise environment. I add new tables/columns, ...
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PostgreSQL partitioned table data model
I have created partition by range based on row_created_tmst for PostgreSQL table. Since partition keys needs to be part of the primary key in PostgreSQL, row_created_tmst is included in the primary ...
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ERD Review, Employee travel lump-sum payment based on rank
I'm building application for employee official travel with lump-sum payment based on the employee group or echelon they have and I need a little help how to store the data correctly, as the problem im ...
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Should a TeamMembers table have a relationship with the Student Table or the Enrolment Table?
I'll keep it nice and short and simply link to the ERD:
Users can be assigned a role, one of those is student.
So for the sake of this, Students are the same as Users!
A Student can be enrolled in ...
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There are 2 ERD Designs, and one has a strange combination. I am told both are correct. why?
One of the designs seems clear: A REQUESTEDPRODUCT is picked from STOCK (which has many locations). The primary key is a composite key of 4 foreign keys.
The other design is more unclear. The "...
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How do I adjust the table link endpoint in PgAdmin's ERD tool after autogenerating it from an existing database?
I can move the lines themselves around, but I can't move the endpoints, which cause the lines to overlap. The only way to understand which relationship is being referenced is by hovering over the ...
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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 ...
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Entity Relationship Diagram for Hotel
I tried creating an ERD model for hotel reservation and billing. Are the cardinalities correct, I'm a bit confused about that. And are there any attributes that are not in the right place? If someone ...
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What arrow is used to specify the relationship between a junction table and the FK tables [closed]
This is part of my first database design. I am unsure what type of arrow to use to describe the relationship:
The tables are parking space, parking space features, and features.
I am unsure of how to ...
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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, ...
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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 ...
CommunityBot
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Relational Model Design - Entity with one attribute
I am trying to design a database relational model for an assignment. First, I design the ER diagram, and then the relational model with tables (schemas).
Here's my question: Is it possible for an ...
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Is it ok to have repeated values in some of the columns and similar columns in two separate tables?
I'm trying to create database in which I could store thousands of job postings. I put here 3 sample records of these job postings so that you could better understand how everything looks like:
Every ...
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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 ...
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One-to-One? or One-to-Zero-or-One?
Scenario: I am being asked to create an HR training tracker for employees of a business. in this database I am using two tables:
EMPLOYEE(EMPLID, LastName, FirstName, PrimaryEmail) with EMPLID as the ...
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Table for an Appointment App
experts,
I am building out an appointment scheduler application. I am seeking advice on how best to tackle this issue.
I am building out my ERD and I am the point where I will be creating a ...
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If an entity's primary key must contain a foreign key, does that make the entity weak?
I'm currently learning about strong and weak entity types in the context of RDBMS. While reading, I came across this statement:
"A weak entity is dependent on a strong entity to ensure its ...
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