# `Ecto.Migration.Constraint`
[🔗](https://github.com/elixir-ecto/ecto_sql/blob/v3.14.0/lib/ecto/migration.ex#L540)

Used internally by adapters.

To define a constraint in a migration, see `Ecto.Migration.constraint/3`.

# `t`

```elixir
@type t() :: %Ecto.Migration.Constraint{
  check: String.t() | nil,
  comment: String.t() | nil,
  exclude: String.t() | nil,
  name: atom(),
  prefix: String.t() | nil,
  table: String.t(),
  validate: boolean()
}
```

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