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Fetch Client Exchange Step

A step definition for processing the target collection.

A fetch client exchange step defines how information about the target collection is processed bySAP Mobile Platform Server. This definition references a step definition within the same module. This step has access to information about the target collection, as well as to any data captured in fetch properties. A client exchange step can be defined to execute once or iteratively, and can return data for an object collection. A fetch can contain multiple client exchange step definitions, which are processed by the Server in a defined order.

Though a client exchange step can return data to create and populate object instances, its intended purpose is to provide information about the current objects stored in the collection property targeted by the parent fetch (target collection) definition. A Client exchange step has access to the key property and last update value for each object instance in the target collection. This information is provided in support of the exchange data model. The intent is that the client exchange steps update this information to an exchange data object in the back end for later comparison to determine which data may need to be retrieved to update the Client.

Client Exchange Step Attributes

  • Step: This attribute references the step definition within the same module to run as a client exchange step for the parent fetch.
  • Run: This attribute specifies how to run the client exchange step during a single transmit. This may be set to one of the following values:
    • Run one Time: This setting will run the client exchange step a single time for the fetch processing. This setting assumes the step needs to be executed only once to return the data for all object instances to be added or replaced during synchronization, or the step being executed is not returning data but rather is being run in support of synchronization.
    • Run Once per Object: This setting will execute the client exchange step once for each object instance in the collection that is being synchronized. This includes both those object instances sent by the Client to the Server, as well as any that may have been added by previous fetch steps.
  • Read Into: This attribute specifies the child or descendent object collection property of the target collection into which the data returned by the step should be read. This attribute has a default setting of “None”. This default means the data will not be read into a child collection but will instead be used to create object instances of the target collection. Other valid options for this attribute are any child collection properties of the target collection, or any descendent collections (e.g. collections within collections).