DBDiff

Multi-database schema comparison and migration CLI tool. Supports PostgreSQL, MySQL, and SQL Server.

Features

• Compare database schemas between two instances
• Generate migration SQL scripts
• Multi-database support: PostgreSQL and MySQL
• Dialect-aware SQL generation (e.g., MODIFY COLUMN for MySQL, ALTER COLUMN TYPE for PostgreSQL)
• Multiple output formats: SQL, Table, JSON
• Dry-run mode (default)
• Schema filtering
• Ignore patterns for columns
• Transaction wrapper support
• SSL/TLS connection support
• Migration tracking

Installation

# Via Go install
go install github.com/meru143/dbdiff@latest

# Via Homebrew
brew install meru143/homebrew-dbdiff/dbdiff

# Via binary
curl -L https://github.com/meru143/dbdiff/releases/latest/download/dbdiff-linux-amd64 -o dbdiff
chmod +x dbdiff

Usage

PostgreSQL

# Compare two PostgreSQL databases
dbdiff compare postgres://user:pass@localhost:5432/db1 postgres://user:pass@localhost:5432/db2

# Generate migration
dbdiff migrate -s postgres://localhost:5432/db1 -t postgres://localhost:5432/db2 -o migration.sql

# Show table diff
dbdiff diff postgres://localhost:5432/db1 postgres://localhost:5432/db2 --format table

MySQL

# Compare two MySQL databases
dbdiff compare mysql://user:pass@tcp(localhost:3306)/db1 mysql://user:pass@tcp(localhost:3306)/db2

# Generate migration
dbdiff migrate -s mysql://user:pass@tcp(localhost:3306)/db1 -t mysql://user:pass@tcp(localhost:3306)/db2 -o migration.sql

SQL Server

# Compare two SQL Server databases
dbdiff compare "sqlserver://sa:Password@localhost:1433?database=db1" "sqlserver://sa:Password@localhost:1433?database=db2"

# Generate migration
dbdiff migrate -s "sqlserver://sa:Password@localhost:1433?database=db1" -t "sqlserver://sa:Password@localhost:1433?database=db2" -o migration.sql

General Commands

# List tables
dbdiff tables postgres://localhost:5432/db

# Validate connection
dbdiff validate postgres://localhost:5432/db

Configuration

Create config.yaml:

source: postgres://user:pass@localhost:5432/db1
target: postgres://user:pass@localhost:5432/db2
output: ./migrations/
format: sql
schema: public
ignore_patterns:
  - "_created_at"
  - "_updated_at"

Supported Databases

Database	Introspection	Migration SQL	Dialect-Aware DDL
PostgreSQL	✅	✅	✅
MySQL 8.0+	✅	✅	✅
SQL Server	✅	✅	✅

Flags

Flag	Short	Description	Default
--source	-s	Source database URL
--target	-t	Target database URL
--output	-o	Output file path	stdout
--format		Output format: sql, table, json	sql
--schema		Database schema	public
--dry-run		Dry-run mode (don't write)	true
--force	-f	Skip confirmation prompt	false
--timeout		Query timeout	30s
--transaction		Wrap in transaction	true
--ssl-mode		SSL mode: disable, require, verify-ca, verify-full	disable
--backup-dir		Backup directory for migrations
--max-backups		Maximum backups to keep	5
--protected-objects		Protected objects (skip in migration)
--ignore-patterns		Columns to ignore
--verbose	-v	Verbose output
--debug		Debug output
--config	-c	Config file path

Environment Variables

Variable	Description
DBDIFF_SOURCE	Source database URL
DBDIFF_TARGET	Target database URL
DBDIFF_LOG_LEVEL	Log level: debug, info, warn, error
DBDIFF_CONFIG	Config file path

Development

Running Tests

# Unit tests
go test ./...

# Integration tests (requires Docker)
docker compose -f docker-compose.test.yml up -d
go run -tags=integration test/integration/main.go
docker compose -f docker-compose.test.yml down

License

MIT License - see LICENSE