DBDiff compares two MySQL, PostgreSQL or SQLite databases, local or remote, and writes the migration that turns one into the other: schema and data, up and down, ready to apply.
When used alongside a compatible database migration tool, it can help enable database version control within your team or enterprise.
--driver--schemas / --ignore-schemas--server1-url, --server2-url, --db-url) — works with any connection string--supabase one-flag shorthand (not required when using DSN URLs)migration:up, down, status, validate, repair, baselineOther versions may work but are not actively tested. PRs to add official support are welcome.
MySQL 8.0, the 8.4 LTS, and current Innovation releases.
Use --driver=pgsql (or driver: pgsql in your .dbdiff config).
PostgreSQL 14 and later. CI tests every supported major version.
pg_dumpDBDiff renders CREATE TABLE and what hangs off it (indexes, constraints,
identity options, collations, storage, compression) in one of two ways:
pg_dump. Used when pg_dump and pg_restore are on PATH and at
least as new as the server. This is PostgreSQL’s own rendering.Both renderers reproduce every case in the
@akal/pg-conformance
corpus on every supported PostgreSQL version. The corpus holds shapes drawn
from PostgreSQL’s own regression suite plus hand-written hard cases. Each one
is built, diffed, applied and compared by catalog fingerprint, on every pull
request.
The migration header records which renderer was used (-- Renderer: pg_dump).
Set DBDIFF_PG_DUMP_RENDERER=off to pin the built-in one for byte-identical
output across machines. DBDIFF_PG_DUMP and DBDIFF_PG_RESTORE override the
binary paths.
Partitioned tables always use the built-in renderer. pg_dump adds a
partitioned parent’s primary key with ALTER TABLE ONLY, which reaches only
the partitions that exist at that moment. The built-in renderer puts the key
inside CREATE TABLE, where every partition inherits it whatever order the
statements run in.
Every PostgreSQL migration DBDiff generates is meant to apply as written and leave the target identical to the source — and to revert cleanly with the DOWN. The cases where that takes more than one statement:
ALTER COLUMN ... TYPE
while a view, materialized view, policy, trigger condition or stored
generated column reads the column. Those are dropped and put back around the
change — views in any schema, and through any partition — with their options
(security_invoker included), grants, comments, INSTEAD OF triggers and
indexes. Grants come back exactly: where default privileges would widen a
recreated view, they are revoked first. A generated column is recomputed from
its expression, so no data is lost. A change that is not a type change — a
default, nullability — leaves them alone.text → uuid, varchar → integer) get
USING column::type, which parses each value and fails loudly on one it
cannot read. Never towards a string type, where an explicit cast would
truncate silently.DROP EXPRESSION, which keeps its values.SET GENERATED, SET INCREMENT
BY ..., a plain TYPE change — so the sequence carries on where it was. A
column becoming an identity, or a serial one becoming an identity or back,
gets a sequence started past the values already in the column, and a serial
column’s old sequence is dropped rather than left behind.SET STORAGE, SET COMPRESSION) are
compared, and set again after a type change, which resets both to the new
type’s defaults.ALTER TYPE ... ADD VALUE ... BEFORE/AFTER,
positioned where the source has it. A label added this way cannot be used
in the same transaction until it commits (unsafe use of new value), so
dbdiff migration:up applies label additions first, each committed, and
then the rest of the migration in one transaction; another runner applying a
whole migration in one transaction should do the same.USING col::text::new, keeping its
data — a row holding a removed label fails the cast, loudly, before anything
has changed. Defaults, CHECK constraints and partial or expression indexes
that name a label, foreign keys between two tables’ columns of the type, and
the views, policies, triggers and generated columns reading them stand aside
and come back; so do the type’s comment and grants.UNLOGGED / LOGGED is compared and ordered by foreign keys,
and storage parameters (fillfactor, autovacuum_*) are compared regardless
of the order they were set in or how a boolean was spelled.What is deliberately not reported as a difference:
REFRESH changes it, no DDL does,
and every dump-based copy starts unpopulated.status IN ('draft', 'active') on a
varchar column renders differently once recreated from its own rendering, as
a dump or a migration does. CHECK constraints, partial indexes, policies,
views, trigger conditions, domain CHECKs and generated-column expressions are
compared by what PostgreSQL makes of them, not by their text.Known limitations:
Use --driver=sqlite. The file path is passed as the database name:
./dbdiff --driver=sqlite server1./path/to/source.db:server1./path/to/target.db
SQLite 3.x is supported (any version supported by the installed pdo_sqlite PHP extension).
--supabase sets driver=pgsql and enables SSL automatically:
./dbdiff --supabase --server1=user:pass@db.xxx.supabase.co:5432 server1.mydb:server1.mydb
Row level security is diffed as a first-class object — policies and each table’s
ENABLE/FORCE ROW LEVEL SECURITY flags — which matters here because RLS is how
Supabase enforces per-row access. A policy dropped or changed between two
environments shows up in the migration instead of passing silently.
DBDiff reads the public schema unless told otherwise, so policies and objects
Supabase keeps in auth, storage and its other managed schemas are outside
the diff. Those are managed by Supabase itself rather than by your migrations.
Schemas of your own are compared with --schemas, or every schema but the
managed ones with --ignore-schemas:
dbdiff diff --supabase --ignore-schemas='auth,storage,realtime,_realtime,_analytics,vault,net,graphql*,supabase_*,pgsodium*,pgtle,extensions' ...
For the rest of a Supabase project, such as storage, auth config, cron, webhooks, Realtime, Vault and grants, use SupaForge. It runs DBDiff for the schema and data and covers the other layers itself.
The databases below work with DBDiff’s existing drivers with no code changes. Unless otherwise noted, these have not been tested by the core team. PRs to add official support are welcome.
--driver=mysql (default)| Database | Notes |
|---|---|
| MariaDB 10.x / 11.x | MySQL wire protocol; minor DDL dialect differences |
| AWS Aurora MySQL | Standard MySQL protocol |
| PlanetScale | MySQL-compatible SaaS |
| Vitess / VTGate | MySQL wire protocol via VTGate |
| Percona XtraDB Cluster | MySQL-compatible; Galera replication metadata ignored |
| TiDB | MySQL-compatible; default port 4000 |
| Dolt | MySQL-compatible, version-controlled; CI-tested |
--driver=pgsql| Database | Notes |
|---|---|
| AWS Aurora PostgreSQL | Standard pgsql connection |
| AWS RDS PostgreSQL | Standard pgsql connection |
| Neon | Standard pgsql; supports branch diffing (see below) |
| AlloyDB (Google Cloud) | Google’s Postgres-compatible offering |
| CockroachDB | Postgres wire protocol; some DDL differences |
| YugabyteDB | Postgres-compatible YSQL layer |
| Multigres | Transparent Postgres proxy; no changes needed |
| TimescaleDB | Postgres extension; hypertable DDL diffs natively |
| pgvector | vector(N) columns and HNSW/IVFFlat indexes diff natively |
Neon’s copy-on-write branching lets you diff any two branches directly:
./dbdiff \
--server1-url postgres://user:pass@main-branch.hostname.neon.tech/mydb \
--server2-url postgres://user:pass@feature-branch.hostname.neon.tech/mydb \
--format=flyway --description=my_feature
Dolt is a MySQL-compatible database with Git-style branching. Each branch is exposed as a separate database:
./dbdiff server1.main:server1.feature_add_users
The quickest way to get started is to download a pre-built release directly from GitHub Releases — no PHP, Node, or Composer required:
| Method | Available on Releases? | Best for |
|---|---|---|
| Pre-built binary | ✅ Yes | Quickest start — zero dependencies |
| PHAR | ✅ Yes | Single portable file; requires PHP ≥ 8.1 |
| npm | ✅ Yes (via registry) | Node.js projects or CI pipelines |
| Docker / Podman | — | Isolated environments, CI, or no local PHP |
| Composer (source) | — | Contributing to DBDiff or PHP integration |
PHP requirement: Pre-built binaries, npm packages, and Docker/Podman images bundle PHP 8.3 — no system PHP needed. The PHAR and Composer installs require PHP ≥ 8.1 on your system.
Download from GitHub Releases. No PHP, Node, or Composer required.
| Platform | Asset |
|---|---|
| Linux x64 (glibc) | dbdiff-linux-x64 |
| Linux x64 (Alpine / musl) | dbdiff-linux-x64-musl |
| Linux arm64 (glibc) | dbdiff-linux-arm64 |
| Linux arm64 (Alpine / musl) | dbdiff-linux-arm64-musl |
| macOS Apple Silicon | dbdiff-darwin-arm64 |
| macOS Intel | dbdiff-darwin-x64 |
| Windows x64 | dbdiff-win32-x64.exe |
| Windows arm64 | dbdiff-win32-arm64.exe |
After downloading, make it executable (Linux/macOS) and optionally move it to your PATH:
chmod +x dbdiff-linux-x64
sudo mv dbdiff-linux-x64 /usr/local/bin/dbdiff
dbdiff --version
npm install -g @dbdiff/cli
dbdiff --version
The correct platform binary is selected automatically at install time. Supported: Linux x64/arm64 (glibc + musl), macOS x64/arm64, Windows x64/arm64.
Packages are also published to GitHub Packages as a mirror. If npmjs.org is unavailable:
npm install -g @dbdiff/cli --registry=https://npm.pkg.github.com
Download dbdiff.phar from GitHub Releases. Requires PHP ≥ 8.1.
chmod +x dbdiff.phar
sudo mv dbdiff.phar /usr/local/bin/dbdiff
dbdiff --version
To build a PHAR locally from source, see Building a PHAR.
Pre-built multi-arch images (linux/amd64 + linux/arm64) are published to GHCR on every release. Both Docker and Podman are fully supported — use whichever is available on your system. No local PHP installation is required.
Docker:
docker pull ghcr.io/dbdiff/dbdiff
docker run --rm ghcr.io/dbdiff/dbdiff --version
docker run --rm ghcr.io/dbdiff/dbdiff --driver=mysql \
--server1=user:pass@host:3306 server1.mydb:server1.mydb
Podman (drop-in replacement — commands are identical):
podman pull ghcr.io/dbdiff/dbdiff
podman run --rm ghcr.io/dbdiff/dbdiff --version
podman run --rm ghcr.io/dbdiff/dbdiff --driver=mysql \
--server1=user:pass@host:3306 server1.mydb:server1.mydb
Podman on Linux runs rootless by default — no daemon required. Install via your package manager:
sudo apt install podman(Debian/Ubuntu) orbrew install podman(macOS).
| Tag pattern | Registry | Description |
|---|---|---|
latest, {version}, slim-{version} |
GHCR | Slim — PHAR + PHP Alpine. For production use / CI. |
full, full-{version} |
GHCR | Full — Composer source install. For development and cross-version testing. |
# Slim image (requires dist/dbdiff.phar — run `vendor/bin/box compile` first)
# Replace 'docker' with 'podman' if using Podman
docker build -f docker/Dockerfile.slim -t dbdiff:slim .
docker run --rm dbdiff:slim --version
# Full image (Composer install from source — no PHAR needed)
docker build -f docker/Dockerfile -t dbdiff:full .
See DOCKER.md for cross-version testing, Podman setup, and start.sh flags.
git clone https://github.com/DBDiff/DBDiff.git
cd DBDiff
composer install --optimize-autoloader
Or as a project dependency:
composer require "dbdiff/dbdiff:@dev"
Or globally:
composer global require "dbdiff/dbdiff:@dev"
After installing from source, continue with Setup.
For source installs (git clone / Composer) only. Binaries, PHAR, npm, and Docker do not require these steps.
dbdiff.yml config file — see File Examples./dbdiff server1.db1:server1.db2Expected output:
ℹ Now calculating schema diff for table `foo`
ℹ Now generating UP migration
ℹ Writing migration file to /path/to/dbdiff/migration.sql
✔ Completed
diff (default command)Flags always override settings in .dbdiff.
| Flag | Description |
|---|---|
--server1=user:pass@host:port |
Source connection. Omit if using only one server. |
--server2=user:pass@host:port |
Target connection (if different from server1). |
--server1-url=<dsn> |
Full DSN URL for source (e.g. postgres://user:pass@host:5432/db). |
--server2-url=<dsn> |
Full DSN URL for target. Supported schemes: mysql://, pgsql://, postgres://, postgresql://, sqlite://. |
--driver=mysql\|pgsql\|sqlite |
Database driver. Defaults to mysql. |
--supabase |
Shorthand for --driver=pgsql + SSL. |
--format=native\|flyway\|liquibase-xml\|liquibase-yaml\|laravel |
Output format. Defaults to native. |
--description=<slug> |
Slug used in generated filenames. |
--template=<path> |
Custom output template. |
--type=schema\|data\|all |
What to diff. Defaults to schema. |
--include=up\|down\|both |
Directions to include. Defaults to up. (all is accepted as an alias for both.) |
--nocomments |
Strip comment headers from output. |
--units |
Mark each change’s statements as one unit: -- dbdiff:unit <Kind> <object> before them, -- dbdiff:end after. For tools that review or apply changes one at a time — an enum label swap, a column type change with its views stood aside or a serial column turned into an identity is several statements that only work together and in order. The markers are SQL comments; the migration runs the same with or without them. |
--config=<file> |
Config file path. Defaults to .dbdiff. |
--output=<path> |
Where to write. A file path for native, liquibase-xml and liquibase-yaml; a directory for flyway and laravel, which name their own files. Defaults to migration.sql in the current directory. |
--memory-limit=<value> |
PHP memory limit for this run (e.g. 512M, 1G, 2G, -1 for unlimited). Overrides the 1G default and any memory_limit setting in your config file. |
--tables=<list> |
Comma-separated table include list (supports globs: *, ?). Only these tables are diffed. Example: --tables=users,orders,wp_*. PostgreSQL with --schemas: a pattern with a schema (app.*, public.orders) matches in that schema only; one without matches the table in every schema. |
--ignore-tables=<list> |
Comma-separated table exclude list (supports globs: *, ?). Example: --ignore-tables=cache_*,temp_* |
--schemas=<list> |
PostgreSQL: the schemas to compare (supports globs). Defaults to public. --schemas='*' compares every schema but the system’s own; --schemas=public,app compares two. Objects outside public are named in full in the migration, and a schema only one side has is created or dropped. |
--ignore-schemas=<list> |
PostgreSQL: schemas to skip (supports globs). On its own, compares every other schema. Example: --ignore-schemas=auth,storage,extensions |
--allow-destructive |
Generate the migration even when it contains data-losing changes. See Destructive Change Protection. |
--debug |
Enable verbose error output. |
server1.db1:server2.db2 |
Databases to compare. Or a single table: server1.db1.table1:server2.db2.table1. |
UP only by default: The generated file includes only the UP (forward) migration by default. To also generate the DOWN (rollback) section, pass
--include=all. Example:dbdiff diff --include=all ...
DSN URLs vs
--serverflags: Use--server1-url/--server2-urlwhen you have a connection string (common with Supabase, Neon, Railway, etc.). Use--server1/--server2when specifying credentials separately.
Passwords with special characters: Embed the password percent-encoded in the URL. Use
dbdiff url:encodeto safely encode any password (seeurl:encodebelow). If dbdiff is not yet installed,scripts/encode-password.shworks without any dependencies.
Memory: The CLI sets a default PHP memory limit of 1G. Diffing very large databases may need more — pass
--memory-limit=2Gon the command line or addmemory_limit: 2Gto your.dbdiff/dbdiff.ymlconfig. The CLI flag always wins over the config file.
url:encode — Password encoderPercent-encodes a raw password for safe embedding in any --server-url connection string.
dbdiff url:encode '<raw password>'
Capture the result directly into a connection flag:
PASS=$(dbdiff url:encode 'my$ecret#pass@word%123')
dbdiff diff \
--server1-url="postgres://user:${PASS}@db.xxxx.supabase.co:5432/postgres" \
--server2-url="postgres://user:pass@db.yyyy.supabase.co:5432/postgres"
Accepts stdin too, for use in pipelines:
echo 'my$ecret#pass' | dbdiff url:encode
All characters except RFC 3986 unreserved characters (A–Z a–z 0–9 - _ . ~) are encoded. This is the safe, zero-guesswork approach for any password — including ones containing @, #, ?, /, +, and literal %.
If dbdiff is not yet installed (e.g. you are setting up CI), use the included bash script instead — no Python, Node, or PHP required:
PASS=$(scripts/encode-password.sh 'my$ecret#pass@word%123')
DBDiff includes a built-in migration runner. All migration:* commands accept:
| Flag | Description |
|---|---|
--db-url=<dsn> |
Full DSN URL for the target database. |
--migrations-dir=<path> |
Override the migrations directory. |
--config=<file> |
Path to dbdiff.yml. |
| Command | Description | Extra flags |
|---|---|---|
migration:new <name> |
Scaffold a new migration file. | --format=supabase — plain .sql (no DOWN); auto-set inside Supabase projects |
migration:up |
Apply all pending migrations. | --target=<version> — stop after this version |
migration:down |
Roll back applied migration(s). | --last=<n> (default 1), --target=<version> |
migration:status |
Show applied vs pending migrations. Adds a Supa? column inside Supabase projects. | — |
migration:validate |
Verify on-disk checksums match the history table. | — |
migration:repair |
Remove failed entries so they can be retried. | --force — skip confirmation |
migration:baseline |
Mark current DB state as the migration baseline. | --baseline-version=<YYYYMMDDHHmmss>, --description=<text>, --force |
DBDiff supports two on-disk formats in the same directory:
| Format | File pattern | Best for |
|---|---|---|
| Native (default) | {version}_{name}.up.sql + optional .down.sql |
New projects, rollback support |
| Supabase | {version}_{name}.sql (UP only) |
Existing supabase/migrations/ directories |
If both formats exist for the same version timestamp, the native .up.sql file takes precedence.
When DBDiff is run inside (or below) a directory that contains supabase/config.toml, it automatically:
supabase/migrations/ (no --migrations-dir needed)migration:new to Supabase format — creating a plain .sql filemigration:status, indicating which migrations Supabase’s own schema_migrations table considers appliedPass --format=native to migration:new to override the auto-detected format.
./dbdiff server1.db1:server2.db2
./dbdiff server1.dev.table1:server2.prod.table1 --nocomments --type=data
./dbdiff --format=flyway --description=add_users --include=all \
server1.db1:server2.db2 --output=./sql/
./dbdiff --driver=pgsql --server1=user:pass@localhost:5432 server1.staging:server1.production
./dbdiff --supabase --server1=postgres:pass@db.xxxx.supabase.co:5432 \
server1.staging:server1.production
./dbdiff --driver=sqlite server1./var/db/v1.db:server1./var/db/v2.db
./dbdiff diff \
--server1-url='postgres://user:pass@db.xxxx.supabase.co:5432/postgres' \
--server2-url='postgres://user:pass@db.yyyy.supabase.co:5432/postgres'
If your password contains special characters, use dbdiff url:encode (see url:encode in the Command-Line API section):
PASS=$(dbdiff url:encode 'my$ecret#pass@word%123')
./dbdiff diff \
--server1-url="postgres://user:${PASS}@db.xxxx.supabase.co:5432/postgres" \
--server2-url='postgres://user:pass@db.yyyy.supabase.co:5432/postgres'
# Scaffold a new migration (DBDiff native format)
./dbdiff migration:new create_users_table
# Scaffold a Supabase-format migration (plain .sql, no DOWN file)
./dbdiff migration:new create_users_table --format=supabase
# Inside a Supabase project, format and directory are auto-detected:
cd my-supabase-project # contains supabase/config.toml
./dbdiff migration:new create_users_table # → supabase/migrations/{ts}_create_users_table.sql
# Apply all pending migrations
./dbdiff migration:up --db-url='postgres://user:pass@localhost:5432/mydb'
# Check status (adds a Supa? column inside Supabase projects)
./dbdiff migration:status --db-url='postgres://user:pass@localhost:5432/mydb'
# Roll back the last migration
./dbdiff migration:down --db-url='postgres://user:pass@localhost:5432/mydb'
# Validate checksums
./dbdiff migration:validate --db-url='postgres://user:pass@localhost:5432/mydb'
When inside a Supabase project (supabase/config.toml present) and the local stack is
running (supabase start), --server1-url is resolved automatically from
supabase status:
# Only supply the remote (production) URL — local stack fills in automatically
./dbdiff diff --server2-url='postgres://user:pass@db.yyyy.supabase.co:5432/postgres'
A single dbdiff.yml file in your project root configures both the diff command and the migration runner. Copy dbdiff.yml.example to get started.
Auto-detected filenames, in priority order:
| Filename | Notes |
|---|---|
.dbdiff |
Legacy — still supported for backwards compatibility |
dbdiff.yml |
Recommended — YAML syntax highlighting, single file for everything |
.dbdiff.yml |
Hidden-file variant |
dbdiff.yaml |
.yaml extension variant |
You can also pass any filename explicitly: ./dbdiff --config=myconfig.yml server1.db:server2.db
dbdiff.yml# ── Diff command (./dbdiff server1.db:server2.db) ─────────────────────────
server1:
user: user
password: password
port: 3306 # MySQL: 3306 | PostgreSQL: 5432
host: localhost
server2:
user: user
password: password
port: 3306
host: host2
driver: mysql # mysql | pgsql | sqlite
type: all
include: all
nocomments: true
# ── Filtering ─────────────────────────────────────────────────────────────
# Include list — only these tables are diffed (supports globs: *, ?).
# When set, only matching tables are included. Omit to diff all tables.
# tables:
# - users
# - orders
# - wp_*
# Exclude list — skip these tables entirely (supports globs).
tablesToIgnore:
- table1
- table2
# Exclude from data diff only — schema is still diffed (supports globs).
# tablesDataToIgnore:
# - audit_log
# - event_stream
# Per-table column exclusion (keys support globs: *, ?).
fieldsToIgnore:
table1:
- field1
- field2
# Per-table row filtering — skip rows matching a column-value regex.
# rowsToIgnore:
# wp_options:
# - { column: option_name, pattern: "_transient_.*" }
# - { column: option_name, pattern: "_site_transient_.*" }
# sessions:
# - { column: status, pattern: "expired|archived" }
# Per-table scope override: schema, data, or all (default).
# tableScope:
# audit_log: schema
# config: data
# ── Migration runner (dbdiff migration:up) ────────────────────────────────
database:
driver: mysql
host: localhost
port: 3306
name: mydb
user: root
password: secret
migrations:
dir: ./migrations
history_table: _dbdiff_migrations
DBDiff offers fine-grained control over what enters the diff. All list values support glob patterns (* matches any characters, ? matches a single character).
| Dimension | Config key | CLI flag | Scope |
|---|---|---|---|
| Table include list | tables |
--tables |
schema + data |
| Table exclude list | tablesToIgnore |
--ignore-tables |
schema + data |
| Schema include list (PostgreSQL) | schemas |
--schemas |
schema + data |
| Schema exclude list (PostgreSQL) | schemasToIgnore |
--ignore-schemas |
schema + data |
| Data-only exclude | tablesDataToIgnore |
— | data only |
| Column exclusion | fieldsToIgnore |
— | schema + data |
| Row filtering | rowsToIgnore |
— | data only |
| Per-table scope | tableScope |
— | override |
Priority: include list is applied first (only matching tables pass), then the exclude list narrows further. tablesDataToIgnore removes tables from data comparison only. tableScope can override a table to schema, data, or all.
Glob examples: wp_* matches all WordPress tables, *_backup matches any table ending in _backup, log_? matches log_a through log_z.
# Only diff tables matching these patterns
tables:
- users
- orders
- wp_*
# Skip these tables entirely
tablesToIgnore:
- cache_*
- _dbdiff_migrations
# Skip data diff for these (schema is still compared)
tablesDataToIgnore:
- audit_log
# Exclude columns per table (keys support globs)
fieldsToIgnore:
users:
- updated_at
- last_login
wp_*:
- ID
# Skip rows matching column-value regex
rowsToIgnore:
wp_options:
- { column: option_name, pattern: "_transient_.*" }
sessions:
- { column: status, pattern: "expired|archived" }
# Override scope per table: schema | data | all
tableScope:
audit_log: schema
config: data
| Object | MySQL | PostgreSQL | SQLite | Notes |
|---|---|---|---|---|
| Tables and columns | ✅ | ✅ | ✅ | Types, defaults, nullability, collation; UNLOGGED and storage parameters on PostgreSQL |
| Keys, indexes, constraints | ✅ | ✅ | ✅ | Including NOT VALID, NULLS NOT DISTINCT, deferrable and cyclic foreign keys |
| Views | ✅ | ✅ | ✅ | |
| Materialized views | — | ✅ | — | Their indexes go with them; whether one is populated is not compared |
| Triggers | ✅ | ✅ | ✅ | |
| Functions, procedures | ✅ | ✅ | — | Overloads are told apart by signature |
| Enum, composite and domain types | — | ✅ | — | Enum labels are added in place, or migrated to a new type when removed or reordered |
| Sequences | — | ✅ | — | Altered in place, so the counter is kept |
| Row level security | — | ✅ | — | Policies, and each table’s ENABLE/FORCE flags |
| Extensions | — | ✅ | — | Created and dropped with the schema they’re installed in; their own objects are never diffed |
| Comments | — | ✅ | — | On every object above, and set again when a change recreates an object |
| Partitions, inheritance | — | ✅ | — | Partition bounds, keys, and a partition’s own constraints and indexes |
| Schemas | — | ✅ | — | With --schemas / --ignore-schemas; a schema only one side has is created or dropped |
| Data | ✅ | ✅ | ✅ | Changed, missing and extra rows, compared by hash in primary-key order |
Expressions in CHECK constraints, partial indexes, policies, views, trigger conditions and generated columns are compared by what PostgreSQL makes of them, not by their text. A dump-and-restore copy therefore doesn’t read as changed.
By default DBDiff refuses to generate a migration that would drop data. If the
diff contains a DROP TABLE or DROP COLUMN, generation stops and the offending
changes are listed:
Destructive changes detected — 2 destructive error(s), 1 warning(s):
[error] drop-table: table `legacy_sessions`
→ Use --allow-destructive to proceed, or archive the table instead.
[error] drop-column: column `users`.`legacy_token`
[warning] drop-view: view `active_users`
Re-run with --allow-destructive to generate the migration anyway.
Two severities:
DROP TABLE and DROP COLUMN, the changes that
destroy rows.A dropped column paired with an added column of the same type on the same table
is treated as a likely rename: it is downgraded from an error to a
possible-rename warning, so it is still reported but no longer blocks.
To proceed anyway, pass --allow-destructive:
dbdiff diff --allow-destructive server1.db1:server2.db2
Or set it permanently in your config file:
allowDestructive: true
Schema comparison is designed around round-trips rather than raw query cost — against a managed database (Supabase, RDS, Neon) network latency dominates, so the number of queries matters far more than how much each one returns.
Two passes keep that number flat as a database grows:
1. Pre-scan: skip tables that are already identical. Before diffing anything, DBDiff asks each side for a hash of every table’s schema in a single query. Tables whose hashes match on both sides are skipped entirely. Comparing production against a staging copy, that’s usually almost all of them.
2. Batch fetch: load the remaining tables together. The tables that do differ are read in a fixed handful of queries per side, however many there are, rather than a set of queries per table.
Together these turn schema diffing from one set of round-trips per table into a constant number, which is what makes diffing a large remote database fast.
Per-driver behaviour:
| Driver | Pre-scan | Batch fetch | Notes |
|---|---|---|---|
| PostgreSQL | Yes | Yes | Both passes active |
| MySQL | Yes | Not needed | A table already resolves in very few queries |
| SQLite | Not needed | Not needed | Local file, no network latency |
Both passes are optimisations only — they never change the generated migration. If an adapter cannot provide hashes, or a table is missing from a batch, DBDiff falls back to fetching that table individually.
Data diffing scales separately, via a streaming sorted-merge that compares row hashes in primary-key order and only fetches rows that actually differ.
DBDiff supports multiple output formats via --format. Use --description=<slug> to customise generated filenames.
--format |
Tool | Language | Output | Notes |
|---|---|---|---|---|
native (default) |
Plain SQL | Any | migration.sql |
Up, down, or both |
flyway |
Flyway | Java | V{ts}__{desc}.sql |
Down adds U{ts}__{desc}.sql (Flyway Teams) |
liquibase-xml |
Liquibase | Java | changelog.xml |
Both directions in one file |
liquibase-yaml |
Liquibase | Java | changelog.yaml |
Both directions in one file |
laravel |
Laravel Migrations | PHP | YYYY_MM_DD_HHMMSS_{desc}.php |
up()/down() methods |
| (template) | Simple DB Migrate | Python | custom | Use --template=templates/simple-db-migrate.tmpl |
Let us know if you’re using DBDiff with other tools so we can add them here.
PHARs are built automatically and attached to every GitHub Release. To build locally from source:
composer install
vendor/bin/box compile
Output: dist/dbdiff.phar — rename and move to /usr/local/bin/dbdiff if desired.
box.jsonis pre-configured with GZ compression andcheck-requirements: falseso the PHAR works correctly when stitched with the static micro SAPI runtime used in the pre-built binaries.
2.1.0 — no v prefix)@dbdiff/cli-* packages to npm (skips any already published)# Build PHAR + tag
scripts/release.sh v2.1.0
git push origin v2.1.0
# Build Linux binaries locally (requires Podman or Docker)
SKIP_PHAR=1 scripts/release-binaries.sh 2.1.0
# Upload assets to an existing GitHub Release
gh release upload v2.1.0 --clobber \
dist/dbdiff.phar \
packages/@dbdiff/cli-linux-x64/dbdiff \
packages/@dbdiff/cli-linux-x64-musl/dbdiff \
packages/@dbdiff/cli-linux-arm64/dbdiff \
packages/@dbdiff/cli-linux-arm64-musl/dbdiff
# Update the Homebrew tap formula
scripts/update-homebrew-formula.sh 2.1.0 ../homebrew-dbdiff
Test DBDiff locally against any combination of PHP and MySQL:
# Single combination
./start.sh 8.3 8.0
# Every combination, in parallel
./start.sh all all --parallel
On every push and pull request, CI runs:
See DOCKER.md for flags covering fast restarts, recording fixtures, and CI usage.
Please read the Contributing Guide before submitting a PR.
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