Transactions

Execute multiple operations atomically.

Sequential Transactions

Array of operations executed in order:

const [user, post] = await prisma.$transaction([
  prisma.user.create({ data: { email: '[email protected]' } }),
  prisma.post.create({ data: { title: 'Hello', authorId: 1 } })
])

All or nothing

If any operation fails, all are rolled back:

try {
  await prisma.$transaction([
    prisma.user.create({ data: { email: '[email protected]' } }),
    prisma.user.create({ data: { email: '[email protected]' } }) // Duplicate!
  ])
} catch (e) {
  // Both operations rolled back
}

Interactive Transactions

For complex logic and dependent operations:

await prisma.$transaction(async (tx) => {
  // Decrement sender balance
  const sender = await tx.account.update({
    where: { id: senderId },
    data: { balance: { decrement: amount } }
  })
  
  // Check balance
  if (sender.balance < 0) {
    throw new Error('Insufficient funds')
  }
  
  // Increment recipient balance
  await tx.account.update({
    where: { id: recipientId },
    data: { balance: { increment: amount } }
  })
})

Transaction options

await prisma.$transaction(
  async (tx) => {
    // operations
  },
  {
    maxWait: 5000,    // Max wait to acquire lock (ms)
    timeout: 10000,   // Max transaction duration (ms)
    isolationLevel: 'Serializable'  // Isolation level
  }
)

Isolation levels

Level	Description
ReadUncommitted	Lowest isolation, can read uncommitted changes
ReadCommitted	Only read committed changes
RepeatableRead	Consistent reads within transaction
Serializable	Highest isolation, serialized execution

Nested Writes

Automatic transactions for nested operations:

// This is automatically a transaction
const user = await prisma.user.create({
  data: {
    email: '[email protected]',
    posts: {
      create: [
        { title: 'Post 1' },
        { title: 'Post 2' }
      ]
    },
    profile: {
      create: { bio: 'Hello!' }
    }
  }
})

Transaction Client

The tx parameter is a Prisma Client scoped to the transaction:

await prisma.$transaction(async (tx) => {
  // Use tx instead of prisma
  await tx.user.create({ ... })
  await tx.post.create({ ... })
  
  // Can call methods
  const count = await tx.user.count()
})

OrThrow in Transactions

Use with interactive transactions:

await prisma.$transaction(async (tx) => {
  // If not found, throws and rolls back entire transaction
  const user = await tx.user.findUniqueOrThrow({
    where: { id: 1 }
  })
  
  await tx.post.create({
    data: { title: 'New Post', authorId: user.id }
  })
})

Best Practices

Keep transactions short

// Good - only DB operations in transaction
const data = prepareData() // Outside transaction
await prisma.$transaction(async (tx) => {
  await tx.user.create({ data })
})

Handle errors

try {
  await prisma.$transaction(async (tx) => {
    // operations
  })
} catch (e) {
  if (e.code === 'P2002') {
    // Handle unique constraint violation
  }
  throw e
}

Use appropriate isolation

// Default is fine for most cases
await prisma.$transaction(async (tx) => {
  // operations
})

// Use Serializable for strict consistency
await prisma.$transaction(
  async (tx) => { /* operations */ },
  { isolationLevel: 'Serializable' }
)

Sequential vs Interactive

Feature	Sequential	Interactive
Syntax	Array	Async function
Dependent ops	No	Yes
Conditional logic	No	Yes
Performance	Better	More flexible
Use case	Simple batch	Complex logic