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Questions tagged [junction-table]

A junction table is a table that contains common fields from two or more tables and is the canonical way to implement Many-to-Many relations in SQL and Relational-type databases.

In database management systems following the relational model, a junction table is a table that contains common fields from two or more tables. It is on the many side of a one-to-many relationship with each of the other tables. Junction tables are known under many names such as bridge table and linking table.

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INSERT auto increment primary keys into another table inside transaction

I have 3 tables recipe, ingredient, and the junction table for the previous two recipes_ingredients recipe: recipe_id | name | process ingredient: ingredient_id | name| type recipes_ingredients: id | recipe_id | ingredient_id When I INSERT a…
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How to manage the insert on a junction table

I have two tables: ingredient and recipe recipe table ----------------------- |recipe_id |name | ----------------------- |1 |Pasta | |2 |Pizza | |3 |Fish | ingredient…
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Get Data from Two Tables Floor Flutter

I want to get data from two tables using floor in flutter, how can I do that? this code for getting data from one table. this function inside database.g.dart: Stream> getItems() { return _queryAdapter.queryListStream( 'SELECT…
mhmd
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MySQL Foreign key constraints (Error in having the same Foreign key Constraints) with Junction tables

I seem to be having an issue implementing a Schema which is direct from the Mysql website. I can't add the image as Stack overflow doesn't allow me to but have added link below to diagram. Employee Table Emp_No. INT(11)…
Daniel Ballinger
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MySql: Select entries with same dependencies in junction table

These are my tables: language language_person person +----+----------+ +----+-----------+-----------+ +----+-----------------+ | id | name | | id | languageId| personId | | id | name | …
xosidat546
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EF Code First Many to Many relationship creates a duplicate joining table?

I'm trying to create a many to many relationship between Product and Category with a joining table using EF 6.4.4 and MySQL 8, but unfortunately without success? public class AppDbContext : DbContext { //Schema Tables public DbSet…
Joseph
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Joining three junction tables

my heads hurt from trying to figure this out! I have three tables -Players -Teams -Games Three junction tables with two columns. -player_teams -teams_games -player_games I need to list all Players who are in a Game (eg: Game_id = 111 from variable)…
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Junction Table & Normalization Question

I am having a hard time trying to figure out if the following design pattern is acceptable. I have the following requirements (and some other more) for a relational model: 1) It must be able to represent applications (such as AppA, AppB, AppC), each…
User
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Junction between categories

I am making a database for a freelance sign language interpreter. I have a subject table tblClient which holds information regarding the freelancer's clients. There is a lookup table tlkClientClientType showing the various types of clients…
Jmax116
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Sequelize many-to-many M:N relationship not functioning. Error: 'SequelizeEagerLoadingError:${model1} is not associated to ${model2}'

I'm trying to make a many to many relationship between users and roles through a predefined table roleUsers. const User = sequelize.define('User', { firstName: DataTypes.STRING, lastName: DataTypes.STRING, email: DataTypes.STRING, …
Hettie McConnell
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Why does Entity Framework add a related record even if it already exists in the database?

Why does Entity Framework add a related record even if it already exists in the database? It should just update the junction table in this case)? I am working with Entity Framework 6, I have a many-to-many relationship between Directors and Movies.…
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Relational databse design to represent similarity between rows of same table

For background purposes: I'm using PostgreSQL with SQLAlchemy (Python). Given a table of unique references as such: references_table ----------------------- id | reference_code ----------------------- 1 | CODEABCD1 2 | CODEABCD2 3…
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Postgres query to find if combination already exist in junction table

I have a simple chat module that allows accounts to create multi-user rooms. Given the below schema - is it possible to create a query that will check if room with given users already exist? If this check could lead to performance issues - can you…
milo
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Should I index my foreign keys if they are already part of a unique constraint?

In Postgresql, I have a table with a unique constraint on two foreign keys like below: CREATE TABLE project_ownerships( id BIGSERIAL PRIMARY KEY, project_id BIGINT REFERENCES projects ON DELETE CASCADE, user_id BIGINT REFERENCES users ON…
kyw
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SQL Junction Table Insertion with crawled data

I have created two tables Industry and Salary with a many to many relationship Industry table Industry PK Salary SalaryID pk Income Year IndustrySalary junction table Industry FK SalaryID FK I have crawled data from two different sites with…
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