QuerySingle<T>
A QuerySingle is a Query which follows relations that should be unique between data types (0..1 and 1..1 cardinalities). It returns the instance related to the origin, following the specified relation(s).
It acts as a syntactic sugar to avoid having a query result structure and get the first value out of it.
A QuerySingle is immutable.
Type Parameters
| Type Parameter |
|---|
T extends CloudObject |
Constructors
new QuerySingle()
new QuerySingle<T>(): QuerySingle<T>
Returns
QuerySingle<T>
Methods
from()
static from<T>(object): QuerySingle<T>
Create a query single from a single node.
See Query.from
Type Parameters
| Type Parameter |
|---|
T extends CloudObject |
Parameters
| Parameter | Type | Description |
|---|---|---|
object | InstanceOrTag | starting node for the graph query single |
Returns
QuerySingle<T>
new query single only accepting 0..1 relations
cast()
cast<S>(type): QuerySingle<S>
See Query.cast()
Type Parameters
| Type Parameter |
|---|
S extends CloudObject |
Parameters
| Parameter | Type | Description |
|---|---|---|
type | Class<S> | the new type |
Returns
QuerySingle<S>
query single on a node of the specified type
execute()
execute(): Promise<T>
Execute the query single, see Query.execute()
Returns
Promise<T>
promise containing the single result or null
executeFromCache()
executeFromCache(): T
Execute the query single on the local data cloud, see Query.executeFromCache()
Returns
T
single result value or null
follow()
follow<D>(relation): QuerySingle<D>
Follow a 0..1 relation See Query.follow()
Type Parameters
| Type Parameter |
|---|
D extends CloudObject |
Parameters
| Parameter | Type | Description |
|---|---|---|
relation | Relation<T, D> | relation to next node |
Returns
QuerySingle<D>
new query single with follow operation