`Singleton`

This reference topic applies to FQL v4. Go to this page for the latest FQL v10 reference topics.

Singleton( ref )

singleton( ref )

Singleton( ref )

Singleton( ref )

Singleton( ref )

Singleton( ref )

Description

The Singleton function produces a set containing the Reference that you provide.

In most cases, functions cast References into sets when necessary. The only case where Singleton is required is to return a set’s events rather than a Reference’s events.

Parameters

Parameter Type Definition and Requirements

Parameter	Type	Definition and Requirements
`ref`	Reference	A reference to a resource, such as a document, collection, database, etc.

ref

Reference

A reference to a resource, such as a document, collection, database, etc.

Returns

A new Set Reference for the set which contains the single ref.

Examples

The following query creates a single-item set from the provided ref:

client.query(
  q.Singleton(q.Ref(q.Collection('posts'), '233286601218720256'))
)
.then((ret) => console.log(ret))
.catch((err) => console.error(
  'Error: [%s] %s: %s',
  err.name,
  err.message,
  err.errors()[0].description,
))

Singleton(Ref(Collection("posts"), "233286601218720256"))

result = client.query(
  q.singleton(q.ref(q.collection("posts"), "233286601218720256"))
)
print(result)

SetRef({'singleton': Ref(id=233286601218720256, collection=Ref(id=posts, collection=Ref(id=collections)))})

result, err := client.Query(
	f.Singleton(f.Ref(f.Collection("posts"), "233555580689580553")))

if err != nil {
	fmt.Fprintln(os.Stderr, err)
} else {
	fmt.Println(result)
}

{map[singleton:{233555580689580553 0xc00009b410 0xc00009b410 <nil>}]}

try
{
    Value result = await client.Query(
        Singleton(Ref(Collection("posts"), "233286601218720256"))
    );
    Console.WriteLine(result);
}
catch (Exception e)
{
    Console.WriteLine($"ERROR: {e.Message}");
}

SetRefV(System.Collections.Generic.Dictionary`2[System.String,FaunaDB.Types.Value])

System.out.println(
    client.query(
        Singleton(Ref(Collection("posts"), "233286601218720256"))
    ).get()
);

{@set = {singleton: ref(id = "233286601218720256", collection = ref(id = "posts", collection = ref(id = "collections")))}}

Singleton(Ref(Collection('posts'), '233286601218720256'))

Singleton(Ref(Collection("posts"), "233286601218720256"))

Query metrics:

bytesIn: 70
bytesOut: 152
computeOps: 1
readOps: 0
writeOps: 0
readBytes: 0
writeBytes: 0
queryTime: 9ms
retries: 0