LiveQuery

public class LiveQuery

A LiveQuery automatically observes database changes and re-run the query that the LiveQuery object is created from. If there is a new query result or an error occurred, the LiveQuery object will report the changed result via the added listener blocks.

  • Returns the Parameters object used for setting values to the query parameters defined in the query. All parameters defined in the query must be given values before running the query, or the query will fail.

    Declaration

    Swift

    public var parameters: Parameters

  • Starts observing database changes and reports changes in the query result.

    Declaration

    Swift

    public func start()

  • Stops observing database changes.

    Declaration

    Swift

    public func stop()

  • Returns a string describing the implementation of the compiled query. This is intended to be read by a developer for purposes of optimizing the query, especially to add database indexes. It’s not machine-readable and its format may change.

    Throws

    An error if the query is invalid.

    Declaration

    Swift

    public func explain() throws -> String

    Return Value

    The implementation detail of the compiled query.

  • Adds a query change listener block.

    Declaration

    Swift

    public func addChangeListener(_ block: @escaping (LiveQueryChange) -> Void) -> NSObjectProtocol

    Parameters

    block

    The block to be executed when the change is received.

    Return Value

    An opaque object to act as the listener and for removing the listener when calling the removeChangeListener() method.

  • Removes a change listener. The given change listener is the opaque object returned by the addChangeListener() method.

    Declaration

    Swift

    public func removeChangeListener(_ listener: NSObjectProtocol)

    Parameters

    listener

    The listener object to be removed.