Std.Db.Repository.optional
1 declaration
fn
optional: &Std.Db.Driver.Rows -> fn(Std.Db.Driver.Rows, Int) -> Result[T, Std.Db.Repository.RowError] -> Result[Option[T], Std.Db.Repository.RowError]This is a callable function.
What it does
At most one row as a value.
For a lookup by something unique, where finding nothing is an ordinary
answer and finding several is still a fault.
Read the signature
- The text after the name is the type checked by Pudu.
- Read arrows from left to right: inputs come first, and the final type is returned.
- & borrows a value for this call instead of moving or copying it.
- Names inside [ ] are type arguments, such as the item type held by a collection.
- Option holds Some(value) or None when no value is available.
- Result makes success and recoverable failure part of the function's type.