select与includeselect选择特定字段可以嵌套select使用减少数据量include包含关联数据返回完整的关联对象两者都是用于返回一些数据只是返回的数据不同。select返回指定字段可以选标量字段也可以选择关系字段而include不能选标量字段只能包含关系。注意使用时select与include不能平级在同一层使用使用上的一个方式关系内部可以继续使用where、orderBy、select、include准备一份数据代码如下// seed.js const { PrismaClient } require(prisma/client) const prisma new PrismaClient() async function main() { await prisma.post.deleteMany() await prisma.user.deleteMany() await prisma.user.create({ data: { email: aliceexample.com, name: Alice, password: hashed_pwd_1, posts: { create: [ { title: Hello Prisma, content: first post, published: true }, { title: Draft post, content: not ready, published: false }, ], }, }, }) } main().finally(() prisma.$disconnect())使用select与include代码如下// index.js const { PrismaClient } require(prisma/client) const prisma new PrismaClient() async function main() { // ---------- 1. 什么都不加只有 User 自身字段 ---------- const plain await prisma.user.findMany() console.log(1. 默认:, JSON.stringify(plain, null, 2)) // ---------- 2. includeUser 全部字段 posts ---------- const withInclude await prisma.user.findMany({ include: { posts: true }, }) console.log(2. include:, JSON.stringify(withInclude, null, 2)) // ---------- 3. select只要列出的字段 ---------- const withSelect await prisma.user.findMany({ select: { id: true, name: true, posts: true, // 关联关系也可以写在 select 里 }, }) console.log(3. select:, JSON.stringify(withSelect, null, 2)) } main().finally(() prisma.$disconnect())看下下面数据输出的区别如下默认没有select与include输出如下[ { id: 1, email: aliceexample.com, name: Alice, password: hashed_pwd_1, createdAt: 2024-05-01T10:00:00.000Z } ]使用select输出如下[ { id: 1, name: Alice, posts: [ { id: 1, title: Hello Prisma, content: first post, published: true, authorId: 1 }, { id: 2, title: Draft post, content: not ready, published: false, authorId: 1 } ] } ]使用include代码结果如下[ { id: 1, email: aliceexample.com, name: Alice, password: hashed_pwd_1, createdAt: 2024-05-01T10:00:00.000Z, posts: [ { id: 1, title: Hello Prisma, content: first post, published: true, authorId: 1 }, { id: 2, title: Draft post, content: not ready, published: false, authorId: 1 } ] } ]一般在实际的生产项目中会混合嵌套使用比如像下面的代码// include 里嵌 select限制关联字段 const a await prisma.user.findMany({ include: { posts: { select: { title: true, published: true }, }, }, }) // 结果User 全字段 posts: [{ title, published }, ...] // select 里嵌 include const b await prisma.user.findMany({ select: { id: true, posts: { include: { author: { select: { email: true } } }, }, }, }) // 结果只有 id posts(全字段 author.email) // 嵌套里加 where / orderBy / take const c await prisma.user.findMany({ select: { id: true, posts: { where: { published: true }, orderBy: { id: desc }, take: 5, select: { title: true }, }, }, })
