Schema Sources

Most pgmagmig commands accept --from-* and/or --to-* options to specify where to read a schema from. Exactly one source must be given per side.

Available sources

Read one or more SQL files and apply them in order to a PGlite instance. The resulting schema is extracted from PGlite’s system catalogs.

Order matters — if 02-tables.sql references a type defined in 01-types.sql, list them in that order.

pgmagmig diff --from-sql 01-types.sql 02-tables.sql --to-sql new-schema.sql

Read a JSON schema file, as produced by pgmagmig extract.

pgmagmig extract --from-sql schema.sql > schema.json
pgmagmig diff --from-json old.json --to-json new.json

An empty schema containing only the public schema (which PostgreSQL always has).

# Generate DDL for a complete schema (from nothing to everything)
pgmagmig diff --from-empty --to-sql schema.sql

Connect to a live PostgreSQL database and extract its schema. The connection uses BEGIN READ ONLY followed by ROLLBACK — nothing is written.

pgmagmig diff --from-database postgres://localhost/prod --to-sql schema.sql

Read all YAML migration files from the directory, apply their up SQL in order to a PGlite instance, and extract the resulting schema.

All migration files must be valid — any file with invalid: true causes an immediate error.

pgmagmig diff --from-migrations-dir ./migrations --to-sql schema.sql