feat: lookups with composite uniques

[davenewza]

Overview

• Support for composite unique lookup on the get, update and delete actions
• Support for unique lookups down relationship paths (on inputs and in expressions)
• Support for reliably checking uniqueness across multiple expression conditions
• If update or delete somehow act on more than one row, then transaction is rolled back
• Missing validations and fixes for unique lookups in general
• Improved validation messaging
• Moved to visitor pattern validation

Composite unique lookups

Composite uniques can now be used to identity a row in the get, update and delete actions in either action inputs or in expressions.

model Product {
    fields {
        name Text
        sku Text @unique
        supplierCode Text
        supplierSku Text
    }

    @unique([supplierSku, supplierCode])

    actions {
        get getProduct(supplierSku, supplierCode)

        get getAppleProduct(supplierSku) {
            @where(product.supplierCode == "APPLE")
        }
    }
}

Unique lookups with relationships

Unique lookups (composite included) can be inferred when travelling down related models. Compare this schema with the one above:

model Product {
    fields {
        name Text
        sku Text @unique
        supplier Supplier
        supplierSku Text
    }

    @unique([supplierSku, supplier])

    actions {
        get getProduct(supplierSku, supplier.code)
    }
}

model Supplier {
    fields {
       code Text @unique
       products Products[]
    }

   actions {
     get getSupplierByProduct(products.sku)
   }
}

Improved validation message

[linear]

KE-1138 Get action 'not a unique field' input error with nested fields in @where

model WeeklyPlan {
    fields {
        weekNumber Number
        user User unique
    }

    actions {
        get getMyWeeklyPlan(weekNumber) {
            where(weeklyPlan.user.identity == ctx.identity)
        }
    }
}

model User {
    fields {
        identity Identity unique
    }
}

[davenewza]

https://linear.app/keel/issue/KE-535/get-update-and-delete-to-support-composite-lookup

[jonbretman]

Looks good to me, some gnarly validation logic there but looks like it's well tested.