EDIFACT: Electronic Data Interchange for Administration, Commerce, and Transport

行政管理、商务与运输用电子资料交换(EDIFACT)是由联合国管理的数据交换标准，是一个多重工业EDI标准。

Structure ==

EDIFACT has a hierarchical structure where the top level is referred to as an ''interchange'', and lower levels contain multiple ''messages'' which consist of ''segments'', which in turn consist of ''composites''. The final iteration is an ''element'' which is derived from the United Nations Trade Data Element Directory (UNTDED) and are normalised throughout the EDIFACT standard.

A group or segment can be mandatory (M) or conditional (C) and can be specified to repeat. For example, C99 indicates between 0 and 99 repetitions of a segment or group, while M99 signifies between 1 and 99 repetitions.

A group, like a message, is a sequence of segments or groups. The first segment or group beneath a group must be mandatory, and the group should be made conditional if the logic of the situation demands it.

Service String Advice UNA Conditional

+----- Interchange Header UNB Mandatory

| +--- Functional Group Header UNG Conditional

| | +- Message Header UNH Mandatory

| | | User Data Segments As required

| | +- Message Trailer UNT Mandatory

| +--- Functional Group Trailer UNE Conditional

+----- Interchange Trailer UNZ Mandatory