Available Checks

DDLCheck includes several checks for common database schema migration issues. Each check looks for a specific pattern in your SQL that might cause problems in production.

Check Categories

The checks are organized into the following categories:

High Severity

These checks identify operations that can cause significant issues:

• add_column_not_null_default: Detects when columns are added with NOT NULL constraints and DEFAULT values
• alter_column_type: Detects ALTER COLUMN TYPE operations that require table rewrites
• drop_table: Detects DROP TABLE operations that could result in data loss
• truncate: Detects TRUNCATE operations which can cause data loss and locks
• update_without_filter: Detects UPDATE statements without WHERE clauses

Medium Severity

These checks identify operations that can cause moderate issues:

• create_index: Detects index creation without the CONCURRENTLY option
• drop_column: Detects DROP COLUMN operations that require table rewrites
• rename_column: Detects column renames that can break dependent objects
• set_not_null: Detects when NOT NULL constraints are added to existing columns

Configuration

You can configure or disable any check in your .ddlcheck configuration file:

# Exclude specific checks
excluded_checks = ["truncate", "drop_table"]

# Override severity levels
[severity]
create_index = "LOW"
add_column_not_null_default = "HIGH"

# Configure individual checks
[create_index]
ignore_non_concurrent = false
min_size_warning = 1000

[update_without_filter]
allowed_tables = ["config", "settings"]

See the Configuration section for more details.

Custom Checks

You can create your own custom checks by implementing the Check base class. See the Custom Checks section for more information.

from ddlcheck.core import Check
from ddlcheck.models import Issue, SeverityLevel

class MyCustomCheck(Check):
    """A custom check implementation."""

    @property
    def id(self) -> str:
        return "my_custom_check"

    @property
    def description(self) -> str:
        return "Detects something important"

    @property
    def severity(self) -> SeverityLevel:
        return SeverityLevel.HIGH

    def check_statement(self, stmt, line):
        # Your implementation here
        return []