Decimal Support for MongoDB

Before General Availability, we had to remove Decimal support because we depend on the MongoDB Rust Driver which doesn’t yet support MongoDB’s Decimal128. Here’s their JIRA ticket.

You can learn more details in this issue.

For now, we suggest using String in place of Decimal. Once the MongoDB Rust Driver supports Decimal128, we’ll re-introduce Decimal support for MongoDB in Prisma

[aladinflux]

We ended up building quite a complex middleware that converts back and forth between Float and Decimal. We couldn’t afford to change all arithmetics within the code base and once Mongodb releases the fix, we reconvert everything again to Decimal arithmetics.

[aladinflux]

Is there a solution to modify prisma’s data validator or maybe processor to convert Decimal objects to Float or String? We have built a new version of our app entirely on the Decimal object and the code uses it everywhere.

We tried building middleware to convert Decimal to Float and keep a backup as String in the metadata of the object (stored as Json) and vice versa, from String/Float when retrieving to Decimal. However, this works only on the model itself but won’t work properly for nested queries and will become very quickly unmanageable because of the amount of deep sub-queries you can do in relations.

I was thinking to simply monkey patch Prisma so that whenever it finds a Decimal object, it simply converts it to Float or String types during creation and vice versa, from String and Float to Decimal based on the field name and model name during data fetch.