The Table Grammar represents the internal structure of the message. Chameleon is designed to protect your code from variations in HL7 message structure. This way, changes in the message structure and moving a particular piece of data from one segment to another will not require code changes.

That's why applications that use Chameleon do not directly access the message fields, but instead use the tables to determine which message fields should be mapped. In object-oriented programming terms, Chameleon encapsulates the message structure; thus shielding your application from changes.