Tagged/delimited string format - Multipart messages

Multipart messaging occurs when you embed a message within another message.

Multipart messages are useful when a message has a format as shown below. The Message Header and Message Trailer act as an envelope for the message body. They have a fixed format, but the Message Body can be defined with different formats.

TDS and multipart messages

A place holder for a message is created by setting the Group composition property of a type to Message. This forces the separation type to become undefined for this type and allows a message to be added at this point within the first message, creating a multipart, or embedded message. Such an embedded message must be specified earlier in the outer message by use of a Message Key.

Each type or group with composition Message must be preceded in the model by a string element whose Interpret Element Value property is set to Message Key. Also, each message that is to be used as an embedded message must have its Message Key value set.

When a message is input to a flow, a string element which has been designated as a Message Key should have a value which corresponds to the Message Key of the next embedded message in the bitstream.

Related Concepts
Tagged/delimited string format
Data element separation
Tagged/delimited string format - Model integrity
Tagged/delimited string format - NULL handling
Tagged/delimited string format - Data conversion
Tagged/delimited string format - Relationship to the logical model

Related Tasks
Creating a multipart message
Configuring Tagged/Delimited String (TDS) properties: Message sets
Configuring Tagged/Delimited String (TDS) properties: Message model objects

Related Reference
TDS message model integrity
Tagged/delimited string format physical properties for message model objects