Embedded Query Language

Fields are designated by the "@" symbol concatenated with the HL7 segment ID followed by the sequence number for the field separated by a period (see sections 2.6.1 and 2.6.2 for definition of segment ID and sequence number). If the field is divided into components, the designation may be suffixed with ".nn," to identify a particular component (a suffix of ".3" indicates the third component of the field); otherwise, the whole field is assumed. If the field is further divided into subcomponents, the designation is suffixed with ".nn.mm," which identifies the component and subcomponent requested by relative position.