This topic describes ACORD AL3 messages.
The basic structure of an ACORD AL3 message is shown
in Figure 1. The curled braces { } are used to
indicate groupigns, but are not actually part of the data stream.
Figure 1. Basic structure
of an ACORD AL3 messageACORD Message
{
Message Header Group;
Transactions Group (containing one or more transactions)
{
Transaction_01
{
Transaction Header Group;
Transaction Control Group (optional);
Data Group Segments (one or more);
}
...
}
Message Trailer Group;
}
There can be one or more transactions included in the Transactions
Group
Each group with an ACORD AL3 message has a header consisting of
a one-digit number, three letters, plus a three-digit total length count.
These first seven characters can be modeled as a tag. The data within the
headers is fixed length. Therefore the header type used for the overall message
can be modeled as follows:
Data Element Separation = Tagged Fixed Length
Length of Tag = 7
The Transaction Group contains other
groups, and is therefore modeled in the same way as the overall message. The
Message Header Group and the Message Trailer group just consist of fixed length
elements, therefore the type used can be modeled as:
Data Element
Separation = Fixed Length
There are two
Data Element Separation methods
particularly suited to handling ACORD AL3 messages:
- Fixed Length AL3 supports basic handling of ACORD AL3
messages, including situations where the message groups conform to a different
version of the ACORD AL3 standard. This is deprecated and will be removed
in a future version of the product and an alternative will be provided.
- Tagged Encoded Length supports handling of more sophisticated
situations, including messages containing message groups unknown to the message
dictionary.
The following sections describe their use: