Messages

This section explains the message related terminology to adopt ION for an application.

Messages are objects used to deliver information between applications. Each message consists of two main parts - header and content.

There are two terms messages and documents that can be used interchangeably most of the time.

Sometimes it is useful to know if the whole message is meant or the message content. The message is used for complete message and the document for message content. The document can also have its own headers and content.

See the message structure in this diagram:

Message structure diagram

In other circumstances it is useful to differentiate between generic message definition and specific message instance. Then the document is used for the generic definition and message for the specific instance.

In Data Fabric, all types of objects including the messages are called objects for example in Atlas or Compass. In Data Catalog, the document schema is called object schema. But for most purposes you can consider that to be the same thing.