leo-claude-mktplace/plugins/data-seed/skills/schema-inference.md

name, description

name	description
schema-inference	Infer data types, constraints, and relationships from ORM models or raw SQL DDL

Schema Inference

Purpose

Parse and normalize schema definitions from multiple ORM dialects into a unified internal representation. This skill enables data generation and validation commands to work across SQLAlchemy, Prisma, Django ORM, and raw SQL DDL without dialect-specific logic in every command.

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Supported Schema Sources

Source	Detection	File Patterns
SQLAlchemy	from sqlalchemy import, Column(, mapped_column(	models.py, models/*.py
Prisma	model blocks with @id, @relation	prisma/schema.prisma
Django ORM	from django.db import models, models.CharField	models.py with Django imports
Raw SQL DDL	CREATE TABLE statements	*.sql, schema.sql, migrations/*.sql
JSON Schema	"type": "object", "properties":	*.schema.json

Type Normalization

Map dialect-specific types to a canonical set:

Canonical Type	SQLAlchemy	Prisma	Django	SQL
string	String(N), Text	String	CharField, TextField	VARCHAR(N), TEXT
integer	Integer, BigInteger, SmallInteger	Int, BigInt	IntegerField, BigIntegerField	INT, BIGINT, SMALLINT
float	Float, Numeric	Float	FloatField	FLOAT, REAL, DOUBLE
decimal	Numeric(P,S)	Decimal	DecimalField	DECIMAL(P,S), NUMERIC(P,S)
boolean	Boolean	Boolean	BooleanField	BOOLEAN, BIT
datetime	DateTime	DateTime	DateTimeField	TIMESTAMP, DATETIME
date	Date	DateTime	DateField	DATE
uuid	UUID	String @default(uuid())	UUIDField	UUID
json	JSON	Json	JSONField	JSON, JSONB
enum	Enum(...)	enum block	choices=	ENUM(...), CHECK IN (...)

Constraint Extraction

For each column, extract:

• nullable: Whether NULL values are allowed (default: true unless PK or explicit NOT NULL)
• unique: Whether values must be unique
• max_length: For string types, the maximum character length
• precision/scale: For decimal types
• default: Default value expression
• check: CHECK constraint expressions (e.g., age >= 0)
• primary_key: Whether this column is part of the primary key

Relationship Extraction

Identify foreign key relationships:

• parent_table: The referenced table
• parent_column: The referenced column (usually PK)
• on_delete: CASCADE, SET NULL, RESTRICT, NO ACTION
• self_referential: True if FK references same table
• many_to_many: Detected from junction/through tables with two FKs and no additional non-FK columns

Output Format

Internal representation used by other skills:

{
  "tables": {
    "users": {
      "columns": {
        "id": {"type": "integer", "primary_key": true, "nullable": false},
        "email": {"type": "string", "max_length": 255, "unique": true, "nullable": false},
        "name": {"type": "string", "max_length": 100, "nullable": false},
        "manager_id": {"type": "integer", "nullable": true, "foreign_key": {"table": "users", "column": "id"}}
      },
      "relationships": [
        {"type": "self_referential", "column": "manager_id", "references": "users.id"}
      ]
    }
  }
}