[英]Prisma 3 relation aggregation (sum)
我在尝试获取相关数据的总和时遇到了一些麻烦。
这是我的架构:
model Vote {
userId Int
user User @relation(fields: [userId], references: [id])
itemId Int
item Item @relation(fields: [itemId], references: [id])
value Int
@@id([userId, itemId])
}
model Item {
id Int @id @default(autoincrement())
userId Int
user User @relation(fields: [userId], references: [id])
listId Int
list List @relation(fields: [listId], references: [id])
votes Vote[]
body String @db.VarChar(255)
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
model List {
id Int @id @default(autoincrement())
userId Int
user User @relation(name: "Ownership", fields: [userId], references: [id])
items Item[]
sharedWith User[] @relation(name: "Shared")
title String @db.VarChar(255)
description String?
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
model User {
id Int @id @default(autoincrement())
email String @unique
password String
name String?
lists List[] @relation(name: "Ownership")
items Item[]
votes Vote[]
sharedWith List[] @relation(name: "Shared")
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
我想要得到的是:
这就是我想出的:
prisma.list.findUnique({
where: { id },
include: {
items: {
include: {
votes: {
include: {
_sum: {
select: {
value: true,
},
},
},
},
},
},
},
})
我根据在网上找到的多个不同的查询(其中大部分在 Prisam Docs 中)构建了查询。
我还注意到 Prisma Docs 缺少很多东西,例如(添加/删除相关数据 - 多对多关系)。 有没有更好的文档,或者像这样的东西的示例项目?
谢谢!
这目前不可能作为单个查询。 您可以做的是在取回这些值后对它们求和。
我基于 StackOverflow 创建了一个类似的示例。 鉴于以下 Prisma 架构:
// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema
datasource db {
provider = "postgresql"
url = env("DATABASE_URL")
}
generator client {
provider = "prisma-client-js"
}
model User {
id Int @id @default(autoincrement())
name String
votes Vote[]
questions Question[]
}
model Question {
id Int @id @default(autoincrement())
question String
votes Vote[]
user User @relation(fields: [userId], references: [id])
userId Int
}
model Vote {
id Int @id @default(autoincrement())
value Int @default(1)
questionId Int
question Question @relation(fields: [questionId], references: [id])
user User @relation(fields: [userId], references: [id])
userId Int
}
您可以编写以下脚本:
import { PrismaClient } from "@prisma/client"
const prisma = new PrismaClient()
async function main() {
const users = await prisma.user.findMany({
include: {
questions: {
include: {
votes: {
select: {
value: true,
},
},
},
},
},
})
for (let user of users) {
for (let question of user.questions) {
let vote_sum = 0
for (let vote of question.votes) {
vote_sum += vote.value
}
;(question as any).vote_sum = vote_sum
}
}
console.dir(users, { depth: Infinity })
}
main().catch((err) => console.error(err))
然后在取回数据后对这些值求和。
如果这对您不起作用,我鼓励您为 Prisma 团队编写功能请求。
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