MongoDB

npm install mongodb

InverseModelModule.forRoot({ url: 'mongodb://host:27017/db' });
InverseModelModule.forRoot({ url: 'mongodb+srv://user:pass@cluster.example.net/db' });

The database is the one in the URL's path.

Inferred schema

A collection has no schema, so its fields are inferred from a sample of 100 documents, read when the app starts:

Values	GraphQL
strings	String
integers	Int
numbers with decimals, or a mix of integers and decimals	Float
booleans	Boolean
dates	DateTime
ObjectIds	ID
Decimal128, Long and other BSON types	String, to keep their precision
objects and arrays	JSON
values of different types in different documents	JSON

• _id becomes id: ID!, and is the primary key.
• Every other field is optional, since any document may leave it out.
• A field that is null in every sampled document is left out.
• A field that appears only in documents outside the sample isn't in the API. Restart the app after adding fields to make them appear.

References

MongoDB has no foreign keys, so references are inferred:

• An id field named author_id or authorId references the author or authors collection, and category_id references categories.
• A DBRef references the collection it names.
• An array of ids named tag_ids or tagIds is a list of tags.

Each reference becomes a relation on both sides. Ids are passed and returned as hex strings; the API converts them to ObjectIds.

Transactions

Hooks run in a transaction only on a replica set or a sharded cluster; a single-node replica set is enough. On a standalone server, transaction.active is false and each write applies on its own. Add ?directConnection=true to the URL to connect to a single-node replica set from outside its network.