Experimental Livebook-friendly DSL for sketching entity-relationship diagrams.

This Lab DSL compiles to the stable, pipe-first Choreo.ERD builders and returns an ordinary %Choreo.ERD{}. Tables can be declared as compact column blocks, while relationship edges expose ERD cardinalities as domain vocabulary.

Examples

iex> import Choreo.Lab.DSL.ERD
...> schema = erd do
...>   users = table("users") do
...>     pk :id, :integer
...>     field :email, :varchar, comment: "unique email"
...>   end
...>
...>   posts = table("posts") do
...>     pk :id, :integer
...>     fk :user_id, :integer
...>     field :title, :varchar
...>   end
...>
...>   one_to_many users ~> posts, "writes", from: :id, to: :user_id
...> end
iex> schema.graph.nodes[:users].columns |> Enum.map(& &1[:name])
[:id, :email]
iex> [meta] = Map.values(schema.edge_meta)
iex> {meta.cardinality, meta.label, meta.from_column, meta.to_column}
{:one_to_many, "writes", :id, :user_id}

Relationship edges can use typed constructors, generic edge, or pipe modifiers:

one_to_many users ~> posts, "writes"
has_many users ~> posts, "writes"
edge users ~> posts, one_to_many: "writes"
users ~> posts |> one_to_many("writes") |> columns(:id, :user_id)

The generic ~> form defaults to :one_to_many, which matches the most common parent-table-to-child-table sketching direction.