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.

Index

Constructors

• constructor

Methods

• cast
• execute
• executeFromCache
• follow
• from

Constructors

constructor

• new QuerySingle<T>(): QuerySingle<T>

• Type parameters

  • T: CloudObject<T>

  Returns QuerySingle<T>

Methods

cast

• cast<S>(type: Class<S>): QuerySingle<S>

• See Query.cast()

  ---

  Type parameters

  • S: CloudObject<S>

  Parameters

  • type: Class<S>

    the new type

  Returns QuerySingle<S>

  query single on a node of the specified type

execute

• execute(context: Context): Promise<T>

• Execute the query single, see Query.execute()

  ---

  Parameters

  • context: Context

  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: Relation<T, D>): QuerySingle<D>

• Follow a 0..1 relation See Query.follow()

  ---

  Type parameters

  • D: CloudObject<D>

  Parameters

  • relation: Relation<T, D>

    relation to next node

  Returns QuerySingle<D>

  new query single with follow operation

staticfrom

• from<T>(object: Tag): QuerySingle<T>

• Create a query single from a single node. See Query.from

  ---

  Type parameters

  • T: CloudObject<T>

  Parameters

  • object: Tag

    starting node for the graph query single

  Returns QuerySingle<T>

  new query single only accepting 0..1 relations