EDI in a nutshell

What is EDI?

Electronic Data Interchange (EDI) is the application-to-application exchange of business documents in a standardized electronic format between business or trading partners.

EDI documents can flow through to the appropriate application on the receiver’s system (e.g. SAP, Oracle, Navision etc.) and data processing can begin immediately, instead of having people involved for manual keying in the relevant data. The most common  business documents exchanged via EDI are purchase orders, invoices and advanced shipping notices.

There are several  EDI standards in use today, including ANSI X12, EDIFACT, EANCOM, etc. And, for each standard there are many different versions like EDIFACT D.96A, EDIFACT D.01B etc. When two trading partners decide to exchange EDI documents, they must agree on the specific EDI standard, version and of course on the content.

Both trading partners typically use an EDI translator or EDI Service Provider to translate EDI messages into inhouse files (e.g. SAP IDoc) before integration in the inhouse system.


What is EDIFACT?

EDIFACT is the acronym for Electronic Data Interchange for Administration, Commerce and Transport.

It is the international standard for Electronic Data Interchange (EDI), which was developed by the United Nations (UN). The standard was approved as the ISO 9735 standard by the International Organization for Standardization (ISO) in 1987. The EDIFACT standard provides rules on how to structure data and standardize messages for multi-industry and multi-country exchange.

EDIFACT is also known as United Nations/Electronic Data Interchange For Administration, Commerce and Transport (UN/EDIFACT).

The work of maintenance and further development of this standard is done through the United Nations Center for Trade Facilitation and Electronic Business (UN/CEFACT) under the UN Economic Commission for Europe (UN/ECE).


EDIFACT 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); these are normalised throughout the EDIFACT standard.

All EDIFACT messages are based on the ISO9735, in which the syntax units are described in detail, and have the following structure:

         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


What is an EDIFACT message?

An EDIFACT message is a single business document. Each EDIFACT message is always identified by a six character name.

Typical EDIFACT messages are the following:
ORDERS - Purchase Order Message
ORDCHG - Purchase Order Change Request Message
ORDRSP - Purchase Order Response Message
DESADV - Despatch Advice Message
INVOIC - Invoice Message

EDIFACT messages are made up of a collection of sequenced segments within defined areas. Some segments may be used in more than one area. Messages begin with the Message Header Segment (UNH) and end with the Message Trailer Segment (UNT).


What is an EDIFACT Segment?

An EDIFACT segment is a collection of logically-related data elements in a fixed, defined sequence. EDIFACT segments contain:
- a three-character alphanumeric code that identifies the segment. This is called the segment tag.
- Variable length data elements. These can be either simple or composite.

EDIFACT segments must be separated by a data element separator (data element delimeter), which is normally "+" and ":", and terminated by a segment terminator, normally "‘".

All segments are fully documented in the United Nations Trade Data Interchange Directory (UNTDID). These tables list the segment position, segment tag and segment name. Segment tables also specify if a segment must appear in a message using the requirements designator "M" (Mandatory) or "C" (Conditional), and how many times a particular segment may repeat (repetition field).

In EDIFACT, there are two kinds of segments: Service Segments and Generic Segments.

Service Segments are:
- Envelopes (UNB-UNZ, UNG-UNE, UNH-UNT)
- Delimiter String Advice (UNA)
- Section Separator (UNS)

Generic Segments are for example:
- BGM for the beginning of a message, which contains the document number
- DTM for dates and times
- NAD for name and address data
- MOA for monetary amounts


What is an EDIFACT Data Element?

A simple data element contains one piece of information.

The composite data element contains more than one piece of information, usually containing qualifiers.

In EDIFACT, all mandatory data elements must contain data. Conditional data elements may or may not contain data, depending on the requirements of the particular transmission.

Since data elements must be accounted for by their position in the segment, if an optional or conditional data element does not have data, that data element must still be accounted for in its position within the segment by using the appropriate number of data element separators to ‘skip over’ the empty field.

Data Elements can have different types: numeric, alphabetical and alphanumeric.


What is an EDIFACT Qualifier?

A Composite Data Element is made up of two or more pieces of data (known as components) which form a single data unit. Typically the first data element is the value, which is being qualified. The second data element is typically the qualifier. These are typically ID (code values) fields. The qualifier gives additional definition to the value.


What is an EDI Mapping?

The act of determining what pieces of information in the company’s database should be placed into each data element of an EDI message or transaction set, or in reverse, what data elements of an EDI message or transaction set should be placed into the company’s database is called Mapping.


What is an EDI Translator?

An EDI Translator or Converter is a software which is used to translate/convert information from an inhouse format to an EDI format or vice versa. It's is also possible to use EDI Cloud Services instead of an Inhouse EDI Translater/Converter.