@sap/cds-compiler/share/messages/redirected-to-ambiguous.md

CDS (Core Data Services) compiler and backends

# redirected-to-ambiguous

The redirected target originates more than once from the original target
through direct or indirect sources of the redirected target.

The message's severity is `Error` and is raised by the compiler.
The error happens due to an ill-formed redirection, which requires changes to
your model.

## Example

Erroneous code example:

```cds
entity Main {
      key id : Integer;
    toTarget : Association to Target;
}

entity Target {
    key id : Integer;
}

view View as select from
    Main,
    Target,
    Target as Duplicate
{
    // ❌ This redirection can’t be resolved:
    Main.toTarget : redirected to View
};
```

Entity `Target` exists more than once in `View` under different table aliases.
In the previous example, this happens through the *direct* sources in the
select clause.
Because the original target exists twice in the redirected target, the compiler
isn’t able to correctly resolve the redirection due to ambiguities.

This can also happen through *indirect* sources.  For example if entity `Main`
were to include `Target`, then selecting from `Target` just once would be
enough to trigger this error.

## How to Fix

You must have the original target only once in your direct and indirect
sources.  The previous example can be fixed by removing `Duplicate` from
the select clause.

```cds
view View as select from Main, Target {
    Main.toTarget : redirected to View
};
```

If this isn’t feasible then you have to redefine the association using a mixin
clause.

```cds
view View as select from Main, Target mixin {
    toMain : Association to View on Main.id = Target.id;
} into {
    Main.id   as mainId,
    Target.id as targetId,
    toMain
};
```

## Related Messages

- `redirected-to-unrelated`
- `redirected-to-complex`