Question​

Is there a way to change which editor opens when I use the --edit flag while creating a migration?

Question​

My revisions table lists the following versions:

mysql> SELECT * FROM  "atlas_schema_revisions";
+-------------------------+---------+-----+
| version                 | applied | ... |
+-------------------------+---------+-----+
| .atlas_cloud_identifier | 0       |     |
| 20251007053111          | 1       |     |
| 20251007051222          | 1       |     |
| 20250618084333          | 1       |     |
+-------------------------+---------+-----+

However, when I inspect the target database, the schema changes from 20250618084333 were never applied. How can I delete the latest row(s) so the revision history reflects the actual state?

Question​

How can I keep a single canonical schema or model and apply it to multiple database drivers (for example, an application Postgres database and a data-lake store) so the two remain in sync?

Given a large database schema, how can I manage schema migration for a single table without affecting the rest of the schema?

Answer​

Atlas supports the --include flag (or the env.include attribute) to scope operations to specific resources. If you need to manage the lifecycle of a single table (or a set of tables), use this flag to avoid changes to the rest of the schema.

For example, to manage the products table in a MySQL database:

atlas schema apply \
  --url "mysql://root:pass@:3308/db" \
  --to "file://schema.sql" \
  --dev-url "docker://mysql/8/dev" \
  --include "products"

If the connection URL is not bound to a schema, specify the schema name in the pattern:

atlas schema apply \
  --url "mysql://root:pass@:3308/" \
  --to "file://schema.sql" \
  --dev-url "docker://mysql/8" \
  --include "db.products"

This command will only apply changes related to the products table, leaving other tables untouched.

atlas schema apply \
  --url "mysql://root:pass@:3308/" \
  --to "file://schema.sql" \
  --dev-url "docker://mysql/8" \
  --include "*.products"

Read more:

• Exclude Tables
• URL Connection Scope
• Declarative Schema Migration

How to inspect an external_schema data source (ORM schema) in atlas.hcl to confirm it loaded correctly?

Why does Atlas not detect PostgreSQL event_trigger objects when using --dev-url with search_path=public?

Question​

What encoding is used by Atlas for schema files? How do you avoid encoding issues with PowerShell on Windows?

Answer​

Atlas uses UTF-8 to encode schema files and migration files generated by Atlas. UTF-8 is the default encoding on nearly all system terminals, but on Windows, PowerShell uses UTF-16 by default. This can cause an encoding issue when Atlas loads the schema files generated by the inspect command.

When working with multiple branches and applying hotfixes directly to production, out-of-order migration conflicts may occur if migration files are created with timestamps that don't reflect the actual merge order.

The Problem​

Consider this scenario:

Initial state:

• Master branch:
  • 001_initial.sql
• Dev branch (PR pending):
  • 001_initial.sql
  • 002_add_posts.sql
  • 004_add_index.sql

After hotfix applied directly to production:

• Master branch:
  • 001_initial.sql
  • 003_hotfix_add_email.sql ← hotfix added
• Dev branch (unchanged):
  • 001_initial.sql
  • 002_add_posts.sql
  • 004_add_index.sql

After merging master into dev - the problem:

• 001_initial.sql - Applied to production
• 002_add_posts.sql - Dev-only, not applied to production
• 003_hotfix_add_email.sql - Applied to production
• 004_add_index.sql - Dev-only, not applied to production

This creates a non-linear migration history where migration files 002 and 004 were created before and after the hotfix timestamp but haven't been applied to production.

Question​

When using Atlas on my macOS, I can run atlas migrate apply without any issues, and it applies the migrations successfully. But when running in CI on linux, I get the following error: Error: checksum mismatch

Answer​

This issue is likely due to differences in line endings between operating systems. macOS uses LF (Line Feed) for line endings, while Windows uses CRLF (Carriage Return + Line Feed). When you run Atlas commands in a Docker container, it may be using a different line ending format than what your migrations were created with.

In version control systems like Git, a changeset represents an atomic unit of change. It groups related file modifications under a single hash, allowing them to be reviewed, applied, or reverted together.

In database migrations, a changeset is a unit of schema or data changes made up of SQL statements stored in a migration file, typically executed together in a single transaction.