| Electronic Data Interchange | |
| Overview |
Electronic Data Interchange (EDI) is the exchange of information transmitted electronically between trading partners. The unit of information being exchanged is a structured collection of data whose format follows a standard defined by a standard body. It is the support of this standard body that makes the classic communication of EDI robust as structured data is transferred uniformly across business space that is both discrete and heterogeneous, and yet the data can be processed transparently.
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Framework EDI (FREDI) currently supports the standards defined by the following standard bodies:
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Both standards are fundamentally the same in the way they define how data must be structured to convey information. The data structures that commonly make up the document are mostly the same: they both have
Furthermore, the rules and syntax that govern how these structures are used are also very similar. For one, the hierarchical relationship of these structures in both controlling agencies match at their hierarchical level: the interchange is a parent to the group, the group to the transaction set or message, which in turn is parent to the data segment, the data segment to the composite element, which in turn is a parent to the data element.
Also, rules on how these data structures are to be included or excluded from the document exist for both standards. For example, rules regarding the required presence of elements in a data segment depending on the presence of other elements in the collection is called Relational Conditions or Syntax Rules in ASC/X12, while in UN/EDIFACT they are called Dependency Notes.
In a nutshell, the EDI document is just a collection of contiguous data segments, separated only by a character (or characters) called a segment terminator. For each interchange, the segment terminator is consistent and absolute -- a deviation to a single character invalidates the document making it impossible to process. The document is dependent on the terminator to separate the fundamental blocks of information that are the data segments, like records in a database.
The data segment is further separated into composite data elements and simple (or standalone) data elements, each separated by the element separator character. The collection of information held by these elements are closely interrelated whereby the presence of each element may depend on the absence or the presence of other elements in the same collection. This governance, including other properties of the collection, provide a specific semantic meaning to the data segment, distinct from that of other data segments.
The composite element (composite data element or composite data structure) contains a collection of component elements . The properties of the composite element is similar to the data segment in that it contains a collection of elements. But it should be viewed more like an element in that it represents a unit of data like other elements, only the data is best represented when additional information is involved. Furthermore, unlike the data segment, the composite element itself cannot contain another composite element, and can only contain single units of data elements referred to as component elements, each separated from the other by a component separator. The component element is actually identical to a simple data element, the difference being that the simple data element is contained by the data segment, and the component element is contained by the composite element.
Finally, the simple data element (or standalone element) is the smallest unit of information in the document. It describes, as well as contain, the actual value of the data. The value itself must adhere to the properties that define the data element such as the data type (numeric, string, etc.), and the minimum and maximum size of the value. Furthermore, the value of the data element may only exist if it fulfills a requirement ruled by the presence of other data elements within the collection.
See Also
