Bulk writes

This guide covers common patterns for bulk writes in FQL. You use bulk writes to create, update, or delete multiple collection documents in a single transaction.

Import documents from a CSV or JSON

You can use the Fauna CLI's import command to import collection documents from a CSV or JSON file:

fauna import --path=./customers.json --collection=Customer
Reference: import

Create multiple documents

Use the forEach() and create() to create a collection document for each element of an object array:

// Create an array of objects that contain document data.
let customers = [
  { firstName: "Ruby", lastName: "Von Rails", email: "ruby@example.com" },
  { firstName: "Scott", lastName: "Chegg", email: "chegg@example.com" },
  { firstName: "Hilary", lastName: "Ouse", email: "ouse@example.com" }
]

// Use `forEach()` to create a `Customer` collection document for each
// element of the previous array.
customers.forEach(doc => Customer.create({ doc }))
// `forEach()` returns `null`.
Reference: forEach(), create()

Edit multiple documents

Use forEach() and update() to iteratively update each document in a set:

// Get a set of `Customer` collection documents with an
// `address` in the `state` of `DC`.
let customers = Customer.where( .address?.state == "DC" )

// Use `forEach()` to update each document in the previous set.
customers.forEach(doc => doc.update({
  address: {
    state: "District of Columbia"
  }
})) // `forEach()` returns `null`.
Reference: forEach(), update()

Delete multiple documents

Use forEach() and delete() to iteratively delete documents in a set:

// Get a set of `Customer` collection documents with an
// `address` in the `state` of `DC`.
let customers = Customer.where( .address?.state == "DC" )

// Use `forEach()` to delete each document in the previous set.
customers.forEach(doc => doc.delete())
// `forEach()` returns `null`.
Reference: forEach(), delete()

Paginate bulk writes

Transactions are subject to size limits.

If you’re performing bulk writes on a large dataset, you can use pageSize() and paginate() to perform the write over several transactions instead of one.

// Get a set of `Customer` collection documents with an
// `address` in the `state` of `DC`. Use `pageSize()`
// and`paginate()` to paginate results and
// limit each page to two documents.
let page = Customer.where( .address?.state == "DC" )
                          .pageSize(2).paginate()

// `paginate()` returns an object. The object's `data` property
// contains an array of `Customer` documents.
let data = page.data

// Use `forEach()` to update each `Customer` document in the
// `data` array.
data.forEach(doc => doc.update({
  address: {
    state: "District of Columbia"
  }
}))

// Project the `after` cursor returned by `paginate()`.
// You can use the cursor to iterate through the remaining
// pages.
page {
  after
}

The query returns an after cursor:

{
  after: "hdWDxoq..."
}

Subsequent transactions use the cursor and Set.paginate() to iterate through the remaining pages:

// Uses `Set.paginate()` to iterate through pages.
let page = Set.paginate("hdWDxoq...")

let data = page.data

data.forEach(doc => doc.update({
  address: {
    state: "District of Columbia"
  }
}))

page {
  after
}
See Pagination

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