# `PhoenixKit.Migrations.Postgres.V58`
[🔗](https://github.com/BeamLabEU/phoenix_kit/blob/v1.7.165/lib/phoenix_kit/migrations/postgres/v58.ex#L1)

V58: Timestamp Column Type Standardization (timestamptz)

Converts ALL timestamp columns across all 68 PhoenixKit tables from
`timestamp without time zone` (aka `timestamp(0)`) to
`timestamp with time zone` (aka `timestamptz`).

This completes the DateTime standardization:
- Steps 1-4 (prior): Elixir schemas → `:utc_datetime` / `DateTime.utc_now()`
- V58: PostgreSQL columns → `timestamptz`

## Why timestamptz?

PostgreSQL `timestamp` stores values without timezone context. While PhoenixKit
always stores UTC, `timestamptz` makes this explicit at the database level and
is the PostgreSQL-recommended type for timestamps. Ecto's `:utc_datetime` type
maps to `timestamptz` natively.

## Conversion Safety

The `up` direction needs no `USING` clause — PostgreSQL implicitly treats
existing `timestamp` values as UTC when casting to `timestamptz`.

The `down` direction requires `USING col AT TIME ZONE 'UTC'` to explicitly
convert `timestamptz` back to `timestamp(0)`.

## Idempotency

All operations check:
- `table_exists?/2` — skip if table doesn't exist (optional modules)
- `column_exists?/3` — skip if column doesn't exist
- `column_is_timestamptz?/3` — skip if already converted (up) or already reverted (down)

# `down`

# `up`

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