How to update a many to many relationship in Prisma? - many-to-many

Question

I am modelling a boxing tournament.
Boxers and Fights have a many-to-many relationship:
A Boxer has many Fights
A Fight has many Boxers (exactly 2)
Here are the models in the schema
model Fight {
id Int #id #default(autoincrement())
name String
boxers BoxerFights[]
}
model Boxer {
id Int #id #default(autoincrement())
name String #unique
fights BoxerFights[]
}
model BoxerFights {
boxer Boxer #relation(fields: [boxerId], references: [id])
boxerId Int
fight Fight #relation(fields: [fightId], references: [id])
fightId Int
##id([boxerId, fightId])
}
When creating a boxer I use the fight's name and the 2 boxer ids:
const fight = await prisma.fight.create({
data: {
name,
boxers: {
createMany: {
data: [
{
boxerId: boxerId1,
},
{
boxerId: boxerId2,
},
],
},
},
},
})
How would I update the fight if a boxer needed to be changed? Something like this? I'm not sure if I use update and set
const fight = await prisma.fight.update({
data: {
name: newName,
boxers: {
set: {
data: [
{
boxerId: newBoxerId1,
},
{
boxerId: newBoxerId2,
},
],
},
},
},
})

Answer 1

Here you go an example how to do that:
const { PrismaClient } = require('#prisma/client')
const prisma = new PrismaClient()
const saveData = async () => {
const boxer1 = await prisma.boxer.create({
data: {
name: 'Boxer1',
},
})
const boxer2 = await prisma.boxer.create({
data: {
name: 'Boxer2',
},
})
const fight = await prisma.fight.create({
data: {
name: 'Fight 1',
boxers: {
createMany: {
data: [
{ boxerId: boxer1.id },
{ boxerId: boxer2.id },
]
},
}
},
select: {
id: true,
name: true,
boxers: {
select: {
boxer: {
select: {
name: true,
}
}
}
}
}
})
console.log(JSON.stringify(fight, null, 2))
const boxer3 = await prisma.boxer.create({
data: {
name: 'Boxer3',
},
})
const fightUpdated = await prisma.fight.update({
where: {
id: fight.id
},
data: {
boxers: {
createMany: {
data: [
{ boxerId: boxer3.id },
]
},
deleteMany: {
OR: [
{ boxerId: { equals: boxer1.id } },
]
}
}
},
select: {
name: true,
boxers: {
select: {
boxer: {
select: {
name: true,
}
}
}
}
}
})
console.log(JSON.stringify(fightUpdated, null, 2))
}
saveData()
In the update you have to remove the previous boxer and the new one :)