Import a Rails schema.rb

db/schema.rb is the best-behaved ORM import format, because it is not a description of your models — it is Rails’ dump of the actual database, regenerated by every migration. It is already a snapshot.

The file

db/schema.rb

If your project uses config.active_record.schema_format = :sql, you have db/structure.sql instead — import that as SQL DDL.

Detection

Adminium detects Rails by ActiveRecord::Schema or create_table calls.

What is read

schema.rb	Becomes
create_table "users"	table
t.string, t.integer, t.datetime, …	columns
The implicit id	primary key
add_foreign_key	foreign key + relation
t.references / t.belongs_to	foreign key column
add_index, t.index	index
unique: true	unique constraint
null: false	non-nullable
default:	default
limit:, precision:, scale:	type refinements

Rails conventions Adminium follows

• id is the primary key, implicit unless id: false or primary_key: "uuid".
• created_at / updated_at (t.timestamps) are recognized as system-managed and default to read-only in forms — you do not hand-edit updated_at.
• t.references :user creates user_id plus a foreign key when foreign_key: true. Without it, Rails creates the column and no constraint — so Adminium sees an integer column, not a relation. This is common in older schemas. Check for add_foreign_key lines at the bottom.

Polymorphic associations do not import as relations

t.references :commentable, polymorphic: true

That is two columns — commentable_id and commentable_type — and no foreign key, because it cannot have one: the target table is a runtime value. Adminium imports both columns and no relation. Nothing is lost that the database ever knew.

Single-table inheritance

type plus the union of every subclass’s columns is exactly what the database holds, and exactly what Adminium imports.

Notes

• Enums. Rails enum lives in the model, not in schema.rb, and is usually backed by an integer or string column. Adminium imports the underlying column. Add an enum override to get a select input with your labels.
• The version line (define(version: 2024_01_15_120000)) is the migration timestamp — useful for knowing how current your dump is.