Understanding the Sun Match Engine

Matching Rules

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. The syntax for this section is:

match-type size null-field function m-prob u-prob agreement-weight disagreement-weight parameters

Table 1 describes each element in a match field row.

Table 1 Match Configuration File Columns

Column Number 

Column Name 

Description 

match-type 

A value that indicates to the Sun Match Engine how each field should be weighted. Each field included in the match string (the MatchingConfig section of the Match Field file) must have a match type corresponding to a value in this column.

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”. 

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 this file or calculated using a logarithmic formula based on the m and u-probabilities (depending on the probability type).


function 

The type of comparison to perform when weighting the field. For information about the available comparison functions, see Match Configuration Comparison Functions for Sun Match Engine (Repository).

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. 

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. 

agreement-weight 

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. 

disagreement-weight 

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. 

parameters 

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 Match Configuration Comparison Functions for Sun Match Engine (Repository).