Round Trip Support¶

A round-trip backend is one where dbwarden can both read schema (via generate-models) and write schema (via make-migrations / migrate).

Supported Backends¶

How Round-Trip Verification Works¶

"First-class" means the round-trip is verified: reverse-engineer a live database with generate-models, feed the output back into make-migrations, and get zero diff.

Per-Backend Details¶

PostgreSQL¶

PostgreSQL is a first-class backend with full round-trip support. All metadata (identity columns, collation, storage, compression, generated columns, fillfactor, tablespace, inheritance, exclude constraints, deferrable foreign keys, and advanced index options) is captured by the snapshot, diffed correctly, and emitted as valid DDL.

See PostgreSQL Deep Dive for the complete list of supported features.

MySQL¶

MySQL is a first-class backend with full round-trip support. All metadata (engine, charset, collation, row format, auto_increment, unsigned columns, ON UPDATE, and column comments) is captured by the snapshot, diffed correctly, and emitted as valid DDL.

See MySQL Deep Dive for the complete list of supported features.

ClickHouse¶

ClickHouse has full round-trip support: generate-models reads schema from a live ClickHouse server, and make-migrations / migrate auto-generates DDL for table operations.

Known edge cases:

• Materialized views are introspected but are not currently emitted as discoverable model tables.
• Some native types (Enum8/Enum16, DateTime64, FixedString, UUID) may map to generic SQLAlchemy types in generated models; the underlying CH types are preserved in CHColumnMeta where possible.
• Replicated engine string arguments and SETTINGS on materialized views require manual review.

See ClickHouse Deep Dive for the complete list of supported features.

SQLite¶

SQLite is a first-class backend with full round-trip support. Table options (WITHOUT ROWID, STRICT), generated columns and column collations are captured by the snapshot, diffed correctly, and emitted as valid DDL. Changes SQLite's ALTER TABLE cannot express are emitted as a table rebuild, and the rollback is the rebuild in the other direction.

SQLite remains the usual choice for a dev_database_url as well; see SQL Translation.

See SQLite Deep Dive for the complete list of supported features.

MariaDB¶

MariaDB is supported as a separate database_type (mariadb), but it does not have round-trip support. You can use MariaDB as a target database for migrations, but generate-models and full schema introspection are not available. Use make-migrations to write migrations manually.