Matching Rules Section (Master Index Match Engine Reference)

Master Index Match Engine Reference

Matching Rules Section

The section after the first line of the match configuration file contains match field rows, with each row defining how a certain data type or field will be matched. These are the rules you specify in the match string you define for a master index application. The syntax for this section is:

match-field size null-field function m-prob u-prob agreement disagreement params data-sources

The following table describes each element in a match field row.

Table 1 Match Configuration File Columns


Column Number	Column Name	Description
1	match-field	A value that indicates to the Master Index Match Engine how each field should be weighted. Each field included in the match string (the MatchingConfig section of mefa.xml) must have a match type corresponding to a value in this column.
2	size	The number of characters in the field on which matching is performed, beginning with the first character. For example, to match on only the first four characters in a 10-digit field, the value of this column should be “4”.
3	null-field	An index that specifies how to calculate the total weight for null fields or fields that only contain spaces. You can specify any of the following values: 0 - (zero) If one or both fields are empty, the weight used for the field is 0 (zero). 1 - (one) If both fields are empty, the agreement weight is used; if only one field is empty, the disagreement weight is used. a# - An “a” followed by a number specifies to use the agreement weight if both fields are empty. The agreement weight is divided by the number following the “a” to obtain the match weight for that field. If no number is specified, the default is “2”. You can specify any number from 1 through 10. d# - A “d” followed by a number specifies to use the disagreement weight if only one field is empty. The disagreement weight is divided by the number following the “d” to obtain the match weight for the field. If no number is specified, the default is “2”. You can specify any number from 1 through 10. Note – In the above descriptions, the agreement and disagreement weights are either specified in the file or calculated using a logarithmic formula based on the m and u-probabilities (depending on the probability type).
4	function	The type of comparison to perform when weighting the field. For information about the available comparison functions, see Master Index Match Engine Comparison Functions and Options. An overview of the comparison functions is provided Table 2
5	m-prob	The initial probability that the specified field in two records will match if the records match. The probability is a double value between 0 and 1, and can have up to 16 decimal points.
6	u-prob	The initial probability that the specified field in two records will match if the records do not match. The probability is a double value between 0 and 1, and can have up to 16 decimal points.
7	agreement	The matching weight to be assigned to a field given that the fields match between two records. This number can be between 0 and 100 and can have up to 16 decimal points. It represents the maximum match weight for a field.
8	disagreement	The matching weight to be assigned to a field given that the fields do not match between two records. This number can be between 0 and -100 and can have up to 16 decimal points. It represents the minimum match weight for a field.
9	params	The parameters that correspond to the comparison function specified in column 4. Some comparison functions do not take any parameters and some take multiple parameters. For additional information about parameters, see Master Index Match Engine Comparison Functions and Options.
10	dataSources	The complete path to any data sources used by the comparison function specific in column 4. You can define as many data sources as there are data sources listed for the comparator in the comparators list file. The default comparators do not use data sources, but you can create a custom comparator that does.