ReferenceCommand line
rent migrate preflight
rent migrate preflight answers three questions without changing the database: can Rent inspect this database, is the proposed SQL valid for its dialect, and which changes are safe, need review, or are destructive?
Review a normal change
rent migrate preflightMigration plan
Database postgres
Changes 2 total (1 safe, 1 review, 0 destructive)
1. SAFE add column public.posts.summary (text)
2. REVIEW create index posts_slug_key on public.posts
Ready: Migration SQL is valid.Safe operations preserve existing rows. Review operations require attention to deployment cost or locking. Destructive operations can discard data and always require explicit approval at application time.
Detect a destructive change
rent migrate preflight --drop-objectsMigration plan
Database postgres
Changes 1 total (0 safe, 0 review, 1 destructive)
1. DESTRUCTIVE drop column public.posts.legacy_slug
Review required: Destructive changes need explicit approval.Produce machine-readable output
rent migrate preflight --format json{
"dialect": "postgres",
"operations": [],
"ready": true,
"rename_suggestions": [],
"summary": {
"destructive": 0,
"review": 0,
"safe": 0,
"total": 0
}
}rename_suggestions lists table and column drop-and-add pairs that look like renames, with the
@@rent.previousName or @rent.previousName hint that would preserve their data.
The JSON form is useful for deployment checks and custom review tooling.