Generator Overview

How Seedling’s auto-detection and generator system works.

Generator Overview

Seedling automatically assigns a generator to every column based on its type, name, and constraints. You can override any column with custom generators via a YAML file.

Auto-Detection

When you run seedling generate without overrides, Seedling inspects each column and selects a generator:

Schema Signal	Detected Generator
serial / bigserial PK	Sequence
FK column	FK pool lookup
varchar / text	Random string
varchar named “email”	Email
varchar named “phone”	Phone
varchar named “url”	URL
boolean / tinyint(1)	Bool
timestamptz / timestamp	Now / Timestamp
date	DateGenerator
numeric / decimal	Numeric
float / double	FloatRange
uuid	UUID
json / jsonb	Random JSON
enum	Random enum value
unique column	Unique constrained variant

Hint System

Column comments in the database schema can provide hints to Seedling:

COMMENT ON COLUMN users.role IS 'generator:weighted_choice';

These hints are stored in the schema file and influence generator selection during auto-detection.

Override System

For full control, provide a generator overrides YAML file to override specific columns.