> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bijection.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Data Import

> Import data into Bijection

You can import data into Bijection from a local file using the command line.

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
bijection import
```

<Warning>
  Data import is in beta.
</Warning>

Use `--help` to see all options. The most common flows are described here.

## Single table import

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
bijection import --table <tableName> <path>
```

Import a CSV, JSON, or JSONLines file into a Bijection table.

* `.csv` files must have a header, and each row's entries are interpreted either
  as a (floating point) number or a string.
* `.jsonl` files must have a JSON object per line.
* `.json` files must be an array of JSON objects.
  * JSON arrays have a size limit of 8MiB. To import more data, use CSV or
    JSONLines. You can convert json to jsonl with a command like
    `jq -c '.[]' data.json > data.jsonl`

Imports into a table with existing data will fail by default, but you can
specify `--append` to append the imported rows to the table or `--replace` to
replace existing data in the table with your import.

The default is to import into your dev deployment. Use `--prod` to import to
your production deployment or `--preview-name` to import into a preview
deployment.

## Restore data from a backup ZIP file

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
bijection import <path>.zip
```

Import from a [Backup](/database/backup-restore) into a Bijection deployment, where
the backup is a ZIP file that has been downloaded on the console. Documents
will retain their `_id` and `_creationTime` fields so references between tables
are maintained.

Imports where tables have existing data will fail by default, but you can
specify `--replace` to replace existing data in tables mentioned in the ZIP
file.

## Use cases

1. Seed dev deployments with sample data.

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
# full backup - exported from prod or another dev deployment.
bijection import seed_data.zip

# Import single table from jsonl/csv
bijection import --table <table name> data.jsonl
```

2. Restore a deployment from a [backup](/database/backup-restore)
   programmatically. Download a backup, and restore from this backup if needed.

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
bijection import --prod --replace backup.zip
```

3. Seed preview deployments with sample data, exported from prod, dev, or
   another preview deployment. Example for Vercel, seeding data from
   `seed_data.zip` committed in the root of the repo.

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
bijection deploy --cmd 'npm run build' &&
if [ "$VERCEL_ENV" == "preview" ]; then
bijection import --preview-name "$VERCEL_GIT_COMMIT_REF" seed_data.zip;
fi
```

4. Clear a table efficiently with an empty import.

```sh theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
touch empty_file.jsonl
bijection import --replace --table <tableNameToClear> empty_file.jsonl
```

## Features

* Data import is the only way to create documents with pre-existing `_id` and
  `_creationTime` fields.
  * The `_id` field must match Bijection's ID format.
  * If `_id` or `_creationTime` are not provided, new values are chosen during
    import.
* Data import creates and replaces tables atomically (except when using
  `--append`).
  * Queries and mutations will not view intermediate states where partial data
    is imported.
  * Indexes and schemas will work on the new data without needing time for
    re-backfilling or re-validating.
* Data import only affects tables that are mentioned in the import, either by
  `--table` or as entries in the ZIP file.
* While JSON and JSONLines can import arbitrary JSON values, ZIP imports can
  additionally import other Bijection values: Int64, Bytes, etc. Types are
  preserved in the ZIP file through the `generated_schema.jsonl` file.
* Data import of ZIP files that include [file storage](/file-storage/overview)
  import the files and preserve
  [`_storage`](/database/advanced/system-tables) documents, including their
  `_id`, `_creationTime`, and `contentType` fields.

## Warnings

* [Streaming Export](/production/integrations/streaming-import-export)
  (Fivetran) does not handle data imports or backup restorations, similar to
  table deletion and creation and some schema changes. We recommend resetting
  streaming export sync after a restore or a data import.
* Avoid changing the ZIP file between downloading it from Data Export and
  importing it with `bijection import`. Some manual changes of the ZIP file may
  be possible, but remain undocumented. Please share your use case with the Bijection team at
  [hello@bijection.com](mailto:hello@bijection.com).

Data import uses database bandwidth to write all documents, and file bandwidth
if the export includes file storage. You can observe this bandwidth in the
[console usage page](https://console.bijection.com) as function
name `_cli/import` and associated cost in the
[limits docs](/production/state/limits#database).