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EDI Definition
EDI or Electronic Data Interchange is the exchange of data in a standard format
between computers without any human intermediary.
EDI Standards
Two widely used standards are X12 (commonly used in U.S.A. and Canada), and
UN/EDIFACT (commonly used in Europe and the rest of the world).
EDI Processes
A typical EDI exchange involves the following processes:
Outbound Process
The Outbound process is
the generating and sending of EDI files. Below are the steps of an
outbound process.
1. Obtain data
from existing system.
2. Generate EDI file.
3. Validate EDI file.
4. Send EDI file to trading partner. Some common methods of
transmission are FTP, HTTP and AS2.
Inbound Process
The Inbound process is
the receiving and translating of EDI files. Below are the steps of an inbound
process.
1. Get EDI
file.
2. Validate and acknowledge EDI file be sending back a TA1, 997 or
CONTRL EDI file.
3. Translate EDI file.
4. Save data to a database.
The EDI file structure
An EDI file is a binary computer file that contains data arranged in units
called data elements. Data elements are separated by element terminators;
and a group of data elements make up a data segment. Data segments are
separated by segment terminators.
Figure 1: A Data Segment
A block of data segments
with data that are inter-dependent to each other is called a group or a
loop. An example of a loop is the N1 loop, which may hold a company's
address information.
Figure 2: An N1 Loop
The section of data
segments that convey a message is called a Transaction Set or Message.
The message itself is sectioned into tables (or areas): the header (or Area 1);
the detail (or Area 2); and the summary (or Area 3).
Figure 3a: An X12 Transaction Set
structure
Figure 3b: A UN/EDIFACT message structure
Transaction
Sets (Messages) can be organized by grouping them by their topics or
functions. A group of Transaction Sets is called a Functional Group.
Functional Groups themselves constitute an interchange. An Interchange is
an electronic equivalent of a letter envelope. It contains the destination
and sender ID of the EDI message, and the date/time stamp of when it was
sent.
Figure
4a: The ASC X12 file structure
Figure 4b: The UN/EDIFACT file structure
The Control Segments are
the header and trailer segments that mark the start and end of their controlling
structure.
- The
Header/Trailer control segments of the Interchange are the ISA/IEA in X12,
and UNB/UNZ in UN/EDIFACT.
- The
Header/Trailer control segments of the Functional Group are the GS/GE in
X12, and UNG/UNE in UN/EDIFACT.
- The
Header/Trailer control segments
of the Transaction Set are the ST/SE in X12, and UNH/UNT in UN/EDIFACT.
For more details about
the differences between X12 and UN/EDIFACT, please read EDI
X12 vs. UN/EDIFACT
The Implementation
Guideline
EDI files cannot be successfully exchanged without an implementation
guideline that has been agreed on by the trading partners. An implementation guideline
is a documentation with a set of rules defining a company's EDI file and how it
should be processed.
For the EDI standard to support all industries and different systems, the standard allows the flexibility for companies to incorporate their
requirements into the standard. These conventions are documented into the
implementation guideline. Therefore the steps to translate an EDI file
normally involves the following:
1. Parse the EDI
file following the standard to obtain data from the EDI file.
2. Map the data
obtained from the EDI file to a database using the instructions from the
implementation guideline.
The steps to generate an
EDI file normally involves the following:
1. Obtain data
from existing system and map them to the standard format following your trading partner's implementation guideline.
2. Construct the
EDI file following the standard's rule.
For more details about
the implementation guideline, please read Creating
an EDI Implementation Guideline.
For a PowerPoint Show
about the basics of EDI, please download "Basics of EDI" part I and II
at http://www.edidev.com/edidev_docupdate.htm
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