Join table
A join table is a relational database table whose rows store key-based associations between records in two other tables, commonly representing a many-to-many relationship.
Grokking Relational Database Design
A junction table is a relational table that represents a many-to-many relationship by storing references to the participating entities.
- How it is used
- Represents many-to-many relationships by placing a junction table between two entity tables.
- How deep it goes
- Works through cardinalities, foreign-key placement, and composite primary keys; it does not show SQL table creation.
- Examples
- Uses author_book for authors and books, purchase_product for purchases and products, and customer_dealer for customers and dealers.
- What you can do after
- Build it from scratch by converting a many-to-many relationship into two one-to-many relationships with a composite key.
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Java Persistence with Spring Data and Hibernate epub
A join table is a relational table that stores key-based links between rows of associated entity tables, commonly for a many-to-many association.
- How it is used
- Represents key-based entity links, including many-to-many relationships and optional associations that avoid nullable foreign keys.
- How deep it goes
- Works through keys, uniqueness constraints, and JPA mappings for several multiplicities, while leaving broader collection-mapping tradeoffs as guidance.
- Examples
- Uses user–billing-details SQL, shipment–item and buyer–item mappings, category–item collections, and a three-key Map association.
- What you can do after
- Apply it via JPA @JoinTable and SQL constraints to map links with the intended optionality and multiplicity.
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Building Web APIs with ASP.NET Core
A junction table is a database table that associates rows from two other tables to represent a many-to-many relationship.
- How it is used
- Represents many-to-many relationships in a table-oriented SQL schema.
- How deep it goes
- Defines the schema role and retrieval cost, but does not provide join-table SQL or CRUD implementation.
- Examples
- Uses BoardGames_Domains and BoardGames_Mechanics in a board-game database schema.
- What you can do after
- Evaluate relational and document-oriented schema choices involving many-to-many data.
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The Well-Grounded Python Developer: How the pros use Python and Flask
An association table is a relational table that records associations between entities from two other tables, typically through foreign keys.
- How it is used
- Models many-to-many relationships such as orders with products or users with followed posts.
- How deep it goes
- Explains foreign-key structure and ORM navigation, then stops short of broader schema constraints or indexing.
- Examples
- Uses Order-Product items and User-Post following records as concrete association-table examples.
- What you can do after
- Apply it via SQLAlchemy to connect two models and navigate their associated objects.
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.NET in Action, Second Edition
A join table is an intermediary database table that stores associations between entities in a many-to-many relationship.
- How it is used
- Maps many-to-many associations between entities in an EF Core relational schema.
- How deep it goes
- Explains automatic table creation, the compound primary key, and foreign keys.
- Examples
- Uses Books and Tags as the entities in a many-to-many relationship.
- What you can do after
- Understand how EF Core represents a many-to-many association in the database.
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Related concepts
- many-to-many relationshipused by · A many-to-many relationship is an association in which multiple instances of each participating entity can relate to multiple instances of the other.
- Entity Framework Coreproduced by · Entity Framework Core is a cross-platform object-relational mapping framework for .NET that enables applications to query and persist data through .NET objects and APIs.
- dependent entitykind of · A dependent entity is an entity whose identification or existence depends on a related owner entity and cannot be fully determined independently.
- one-to-one relationshipused by · A one-to-one relationship is an association in which each instance of either entity type relates to at most one instance of the other type.
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