For a data pattern separation type, each data value is matched with a regular expression that is specified as a property of each element.
The Data Pattern separation type uses a regular expression that is specified for each element to match the data. The parser matches the data with the regular expression in the Data Pattern property for that element. TDS parsing in the MRM parser uses the regular expression in Data Pattern to determine the length of the element, whether it is repeating, and whether it is present in the bit stream.
No delimiters or tags, other than those coded as part of the regular expression pattern, are used in the bit stream. See Using regular expressions to parse data elements for an explanation of pattern matching.
DT31758934information for you
The first data pattern means "from one to three characters in the range A to Z", the second means "one or more characters in the range 0 to 9", and the third means "zero or more characters in the range a to z". Note how each element's data was terminated by the first character that did not match the element's Data Pattern.
The parsing required in Data Pattern separation type is the slowest of all the different separation types because of its complexity.
Therefore, use Data Pattern separation type only when no other separation type models the message. Do not use it, for example, when you could use Fixed Length separation type.