How to Export a Schema in BigQuery

How do I export a BigQuery table or dataset schema?

Exporting a schema in BigQuery outputs the table or dataset structure to a JSON file for version control, migration, or documentation.

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Description

Why would I export a BigQuery schema?

Exporting lets you track schema changes, replicate tables across projects, and document data contracts. It’s faster than recreating tables manually.

What tools can run an export?

The bq CLI, Cloud Console, and INFORMATION_SCHEMA views all support schema export. The CLI is script-friendly and preferred for CI/CD pipelines.

How do I export a single table schema?

Run bq show --schema --format=prettyjson project:dataset.table > file.json. The command writes a JSON array of field definitions.

Example

bq show --schema --format=prettyjson galaxy:ecommerce.Customers > customers_schema.json

How do I export every table in a dataset?

Loop through table names returned by bq ls or INFORMATION_SCHEMA and call bq show --schema for each. Store each JSON in version control.

Can I export via SQL only?

Yes. Query INFORMATION_SCHEMA.COLUMNS and save the results. The output isn’t identical to the CLI JSON but contains column names, types, and positions.

Best practices for schema exports

Keep exports in the same repo as code, automate nightly runs, and diff schemas in pull requests to spot breaking changes early.

How do I re-create a table from an exported schema?

Use bq mk --table --schema=path/to/schema.json project:dataset.table. The JSON must match BigQuery’s field format.

Why How to Export a Schema in BigQuery is important

How to Export a Schema in BigQuery Example Usage


--Export the full Orders schema to JSON
bq show --schema --format=prettyjson galaxy:ecommerce.Orders > orders_schema.json

--Export schema via SQL for documentation
SELECT column_name, data_type, is_nullable
FROM `galaxy.ecommerce.INFORMATION_SCHEMA.COLUMNS`
WHERE table_name = 'Orders'
ORDER BY ordinal_position;

How to Export a Schema in BigQuery Syntax


bq show [FLAGS] --schema --format=prettyjson [PROJECT_ID]:[DATASET].[TABLE] > [OUTPUT_FILE]

FLAGS
  --project_id              Override default project
  --dataset_id              Specify dataset (if table omitted)
  --schema                  Return only schema information
  --format=prettyjson|json  Output style

# Ecommerce example: export Orders table schema
bq show --schema --format=prettyjson galaxy:ecommerce.Orders > orders_schema.json

Common Mistakes

Skipping --format=prettyjson. A plain JSON or default table format breaks when piping to a file. Always specify --format=prettyjson for valid schema JSON.
Redirecting without write permission. Using ">" in a protected directory fails silently. Confirm the output path is writable or specify an absolute path.