[Solved] You want to design a GraphQL schema for a blog where each Category has many Posts,... Which schema design correctly models this one-to-many relationship and allows querying all posts in a category? | GraphQL

GraphQL - Type Relationships

You want to design a GraphQL schema for a blog where each Category has many Posts, and each Post belongs to one Category. Which schema design correctly models this one-to-many relationship and allows querying all posts in a category?

Atype Category { id: ID! name: String! post: Post } type Post { id: ID! title: String! category: Category } Query { posts: [Post!]! }

Btype Category { id: ID! name: String! posts: [Post!]! } type Post { id: ID! title: String! categoryId: ID! } Query { category(id: ID!): Category }

Ctype Category { id: ID! name: String! posts: Post } type Post { id: ID! title: String! categoryId: ID! } Query { category(id: ID!): Category }

Dtype Category { id: ID! name: String! posts: [Post] } type Post { id: ID! title: String! category: Category! } Query { category(id: ID!): Category }

Step-by-Step Solution

Solution:

Step 1: Model one-to-many with list in Category
Category should have posts as a list [Post!]! to represent many posts.
Step 2: Use categoryId in Post to link back
Post has categoryId to link to its single category, enabling queries from both sides.
Step 3: Check Query type for fetching category
Query allows fetching category by id, then posts can be queried from category.
Final Answer:
type Category { id: ID! name: String! posts: [Post!]! } type Post { id: ID! title: String! categoryId: ID! } Query { category(id: ID!): Category } -> Option B
Quick Check:
List in parent + foreign key in child = one-to-many [OK]

Quick Trick: Parent has list, child has foreign key ID for one-to-many [OK]

Common Mistakes:

Using single Post instead of list in Category
Missing foreign key in Post
Incorrect Query type for fetching data

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More GraphQL Quizzes

Which schema design correctly models this one-to-many relationship and allows querying all posts in a category?

Step 1: Model one-to-many with list in Category

Step 2: Use categoryId in Post to link back

Step 3: Check Query type for fetching category

Final Answer:

Quick Check:

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