DbCodec

Returns a derivation builder for DbCodec so callers can attach precise field/type overrides before deriving the final codec.

Derives a DbCodec after applying caller-supplied derivation-builder overrides such as field-level custom codecs.

Auto-derives a DbCodec[B] from DbCodec[A] and As[A, B].

This enables Scala 3 opaque types and ZIO Prelude Newtype/Subtype values to receive a DbCodec for free when their underlying type already has one:

opaque type ProductId = String
// provide As[String, ProductId] in the ProductId companion object
// DbCodec[ProductId] is then resolved automatically — no explicit given needed

This given is lower priority than any explicit given DbCodec[B] or derived because it lives in the companion object at the same level as primitive codecs but is polymorphic (two type parameters), making it less specific than any monomorphic given for a concrete type B.

Use DbCodec[A].transform for types that do not have an As instance.

Derives a DbCodec[A] using the default column name mapper. Self-contained: derives Schema[A] internally, so no Schema needs to be in scope. Enables the Scala 3 derives clause: case class User(...) derives DbCodec

Auto-derives a DbCodec[A] for Scala 3 opaque types by reusing the codec of the underlying type. The opaque type companion must expose a public apply method from the underlying type to the opaque type, so decode uses the same validation/wrapping path as user code.

For encoding, either define the opaque type as a subtype of the underlying type:

opaque type ProductId <: String = String
object ProductId { def apply(value: String): ProductId = value }

or provide a public unwrap method:

opaque type ProductId = String
object ProductId {
 def apply(value: String): ProductId = value
 def unwrap(value: ProductId): String = value
}

This given lives in a super-trait so it has lower priority than derived (requires Schema) and dbCodecFromAs (requires As), both of which are defined in object DbCodec itself.