Load Existing Data from a Hasura Database using Netlify Serverless Functions
We'll load existing data from our Hasura database using serverless functions. The first step will be to create a new mutation in the Hasura GraphiQL named InserOrUpdateBoops.
We need to make sure that all the corgis are being loaded into our database. Once they are loaded, we can set the count to zero. We do this by defining a GraphQL mutation using an autogenerated variable provided by Hasura called, boops_insert_input!.
Our application loads the existing data but the functionality to save the values from the client-side is still not available.
Could you please help and elaborate how is this working? mutation MyMutation($likes: [likes_insert_input!]!) { likes: insert_likes(on_conflict: {constraint: likes_pkey, update_columns: id}, objects: $likes) { returning { count id } } } I understand what it is doing, but its confusing a bit. Thank you in advance!
sure!
Hasura supports "upserts", meaning it will create OR update something in the database, which is a nice convenience method to avoid needing a strict "create" and "update" function and needing to reason about when to use each one
to support this, we need to know what to update when a conflict (an existing entry with the same key) is found
so the constraint identifies the key that means a conflict exists, and the update_columns identifies which fields should be updated. any fields that are not included in that will be ignored
this is especially useful if you have something with partially sensitive data. imagine a User and they have permission to edit their name and email, but not their permission level — the constraint would be their user ID, and the update_columns would be name and email
let me know if that doesn't make sense!