Hi I am trying to apply like preoperation on my model like if I have model like

{
a Int
b Int 
c Int 
sum Int
}

is there any way to calculate and assign this `sum as the value of a,b,c`without applying in node js like I see in nosql data

@Shubham Singh 👋 Are you using Postgres? If so, you can first create the model in your

schema.prisma

as follows:

model Data {
  id  Int @id @default(autoincrement())
  a   Int
  b   Int
  c   Int
  sum Int
}

Then run the following command:

prisma migrate dev --create-only --preview-feature

Alter the created

.sql

file in the

migrations

folder to:

CREATE TABLE "Data" (
    "id" SERIAL,
    "a" INTEGER NOT NULL,
    "b" INTEGER NOT NULL,
    "c" INTEGER NOT NULL,
    "sum" int generated always as (a + b + c) stored,

    PRIMARY KEY ("id")
);

This will always calculate the sum field as a combination of the three values.

generated always as (a + b + c) stored

i have a hard time looking this up on Prisma docs, do you have a link for this? thanks @Ryan

This isn’t Prisma specific as it’s a Postgres feature: https://www.postgresql.org/docs/12/ddl-generated-columns.html 🙂

ah got it. thanks!

Thanks ryan for helping me out I was confused with that