The DataLoader triggers multiple queries when fetching related entities.

[praveengopalan]

Hi Team,
I'm new to GraphQL and currently working on a project that involves related entities such as Order and OrderDetails. I'm using a group DataLoader to fetch OrderDetails, but when I run the following query, it results in two separate database queries:

query Orders {
Orders {
nodes {
id
orderDesc
OrderDetails {
item
amount
quantity
}
Details {
item
amount
quantity
id
}
}
}
}

SELECT id, orderdesc FROM Order
SELECT item, amount, quantity FROM OrderDetails

Is this the expected behavior?
Additionally, is there a more efficient way to execute this query in a single round trip?

Thanks.

[PascalSenn]

Hi @praveengopalan,

Yes — this is the expected behavior when using a group DataLoader. The DataLoader batches the calls efficiently, so even though you see two database queries (Order and OrderDetails), they are grouped and only executed once per data source, which scales well.

If you want to reduce it to a single query round trip, you can look into using projections or a more optimized data access pattern. With projections, you can shape the result so that Order and its related OrderDetails are fetched together in one query

However, keep in mind:

• Batched queries like you currently have scale better in many cases because they decouple fetching from different tables and allow better reuse and caching.
• A single large join query can sometimes hurt performance if you have a lot of rows on the child side (OrderDetails), so it’s a tradeoff.