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Version: Next

squash

Squash a range of migrations into a single migration.

Why use it

  • Reduce clutter when many small migrations accumulate over time.
  • Combine related schema changes into one clean migration for easier review and maintenance.
  • Simplify migration history before merging a feature branch.

Usage

npx durcno squash <start> <end> [--config path/to/durcno.config.ts] [--force]

Arguments

  • <start> — the folder name of the first migration in the range. Use npx durcno status to find migration identifiers.
  • <end> — the folder name of the last migration in the range.

Common options

  • --config <path> — Path to config file (defaults to durcno.config.ts).
  • --force — Squash even if custom statements (ddl.custom(...)) exist in the migration range. Without this flag, the command will abort when custom statements are detected because they cannot be preserved during squash.

What it does

  1. Replays all migrations before the range to build a baseline snapshot.
  2. Replays all migrations through the range to build the target snapshot.
  3. Generates a single squashed up.ts and down.ts by diffing the two snapshots.
  4. Deletes all migration folders in the range.
  5. Writes the squashed migration into a single folder using the start migration's timestamp as its name.

Example

Suppose you have three migrations from iterating on a feature:

migrations/
├── 2025-10-01T10-00-00.000Z/   # created users table
├── 2025-10-02T12-30-00.000Z/   # added bio column
└── 2025-10-03T09-15-00.000Z/   # added age column

Squash them into one:

npx durcno squash 2025-10-01T10-00-00.000Z 2025-10-03T09-15-00.000Z

Result:

migrations/
└── 2025-10-01T10-00-00.000Z/   # creates users table with bio and age

The squashed migration's up.ts contains the full combined effect of all three original migrations, and its down.ts reverses everything back.

Important notes

  • Custom statements: If any migration in the range contains ddl.custom(...) statements, the squash will abort unless you pass --force. Custom statements cannot be automatically preserved because they are opaque to the snapshot diffing process.
  • Only unapplied migrations: Squash operates on migration files only. If the migrations in the range have already been applied to a database, the squashed result will be equivalent but the migration history in that database will still reference the original individual migrations.
  • Single migration range: If the range contains only one migration, the command exits early with no changes.

Next: verify the result with npx durcno status.