# `StatifierPersistence.Ecto.Migrations.V01`
[🔗](https://github.com/riddler/statifier_persistence/blob/v0.25.1/lib/statifier_persistence/ecto/migrations/v01.ex#L2)

V01 of the package DDL: the `charts`, `positions`, and `executions` tables
per ADR-0002 (as amended) and the storage contract's field set
(ADR-0003 decision 3).

Table names, the surrogate primary key's column type, and the Postgres
schema all come from the resolved `StatifierPersistence.Ecto.Config` -
the same struct the generated schemas are built from. The engine
identity columns (`content_hash`, `session_id`, `execution_id`) are `text`
with their unique indexes regardless of the configured key scheme:
the identity guard never touches a surrogate key.

This migration always emits `:binary` (`bytea`) for the three blob
columns (`identity_blob`, `chart_blob`, `position_blob`) and does
not read `Config`'s `:blob_type` option. A custom `:blob_type` whose
underlying database type is still binary (an envelope-encrypting
type that dumps to and loads from raw bytes, for example) needs no
DDL change - this migration already matches it. A `:blob_type` that
dumps to a different underlying type (text, jsonb, a Postgres
domain) needs the host to alter those three columns itself; this
helper does not do it for them.

Each of the three tables carries the host's `:leading_columns`, if it
configured any, immediately after `id` and in the order given - the
one place a column the host owns can sit at a fixed ordinal position,
since a column a later `ALTER TABLE` adds lands at the end. They are
added as configured and nothing more: a default or a `NOT NULL` is a
later migration of the host's own.

Two further options shape these three tables and nothing else. Under
`timestamps_position: :leading` the `inserted_at` / `updated_at` pair
follows the leading columns instead of closing each table, and
`:column_collations` gives a text column declared here the collation
named for it. Both exist so a host that once wrote these tables by
hand can be matched column for column; the default for each is the
layout above, unchanged.

# `down`

```elixir
@spec down(StatifierPersistence.Ecto.Config.t()) :: :ok
```

Drops the V01 tables in reverse creation order.

# `up`

```elixir
@spec up(StatifierPersistence.Ecto.Config.t()) :: :ok
```

Creates the V01 tables and their unique indexes per `config`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*