diff Command¶

Show structural differences between models and database.

Description¶

The diff command compares your SQLAlchemy model definitions against the actual database schema to identify discrepancies.

Usage¶

dbwarden diff [type]

Arguments¶

Argument	Description
`type`	Type of diff: `models`, `migrations`, `all` (default: `all`)

Options¶

Option	Description
`--verbose`, `-v`	Enable verbose logging

Examples¶

Compare Models vs Database¶

dbwarden diff

Verbose Output¶

dbwarden diff --verbose

What It Shows¶

New Tables (in models, not in DB)¶

Tables defined in your models but not yet created in the database.

Missing Columns (in DB, not in models)¶

Columns in the database that don't have corresponding model definitions.

Type Mismatches¶

Columns where the data type differs between model and database.

Missing Indexes¶

Indexes that exist in models (via SQLAlchemy) but not in database.

Use Cases¶

Before Migration¶

Check what will be created:

dbwarden diff
# Shows tables/columns that need to be added

After Migration Issues¶

Debug schema inconsistencies:

dbwarden diff
# Shows discrepancies

Schema Drift Detection¶

Identify when database schema doesn't match code:

dbwarden diff
# Compare current state

Requirements¶

For diff to work effectively:

Models must be defined: SQLAlchemy models in models/ directory
model_paths: Must be set in warden.toml or auto-discovery must find models
Migrations table exists: At least one migration applied

Troubleshooting¶

No Models Found¶

No SQLAlchemy models found. Please:
  1. Create models/ directory with your SQLAlchemy models
  2. Or set model_paths in warden.toml

Set model paths in warden.toml:

model_paths = ["models/", "app/models/"]

No Migrations Table¶

No migrations table found. Run 'dbwarden migrate' first.

Apply at least one migration before using diff.

Best Practices¶

Run before migrations: See what changes are pending
Run after issues: Debug schema problems
Use with check-db: Combine for comprehensive view