Skip Headers
Oracle® Database PL/SQL Packages and Types Reference
12c Release 1 (12.1)

E17602-14
Go to Documentation Home
Home
Go to Book List
Book List
Go to Table of Contents
Contents
Go to Index
Index
Go to Master Index
Master Index
Go to Feedback page
Contact Us

Go to previous page
Previous
Go to next page
Next
PDF · Mobi · ePub

256 UTL_MATCH

The UTL_MATCH package facilitates matching two records. This is typically used to match names, such as two First Names or two Last Names.

This chapter contains the following topics:


Using UTL_MATCH


Overview

"Edit Distance" also known as "Levenshtein Distance "(named after the Russian scientist Vladimir Levenshtein, who devised the algorithm in 1965), is a measure of Similarity between two strings, s1 and s2. The distance is the number of insertions, deletions or substitutions required to transform s1 to s2.�

The Edit Distance between strings "shackleford" and "shackelford" = 2

The "Jaro-Winkler algorithm" is another way of calculating Edit distance between two strings. This method, developed at the U.S. Census, is a String Comparator measure that gives values of partial agreement between two strings. The string comparator accounts for length of strings and partially accounts for typical human errors made in alphanumeric strings.

Table 256-1 shows similarity values returned by Jaro-Winkler and Edit Distance

Table 256-1 Comparison between normalized values returned by Jaro-Winkler and Edit Distance algorithms

String 1 String 2 Jaro Winkler Edit Distance

Dunningham

Cunnigham

89

80

Abroms

Abrams

92

83

Lampley

Campley

90

86

Marhta

Martha

96

67

Jonathon

Jonathan

95

88

Jeraldine

Geraldine

92

89



Security Model

The UTL_MATCH package runs with definer's rights. UTL_MATCH must be created under SYS. Operations provided by this package are performed with SYS privileges.


Summary of UTL_MATCH Subprograms

Table 256-2 DBMS_ALERT Package Subprograms

Subprogram Description

EDIT_DISTANCE Function

Calculates the number of changes required to transform string-1 into string-2

EDIT_DISTANCE_SIMILARITY Function

Calculates the number of changes required to transform string-1 into string-2, returning a value between 0 (no match) and 100 (perfect match)

JARO_WINKLER Function

Calculates the measure of agreement between string-1 and string-2

JARO_WINKLER_SIMILARITY Function

Calculates the measure of agreement between string-1 and string-2, returning a value between 0 (no match) and 100 (perfect match)



EDIT_DISTANCE Function

This function calculates the number of insertions, deletions or substitutions required to transform string-1 into string-2.

Syntax

UTL_MATCH.EDIT_DISTANCE (
   s1  IN  VARCHAR2, 
   s2  IN  VARCHAR2) 
 RETURN PLS_INTEGER;�

Parameters

Table 256-3 EDIT_DISTANCE Function Parameters

Parameter Description

s1

The string to be transformed

s2

The string into which s1 is to be transformed


Examples

SELECT UTL_MATCH.EDIT_DISTANCE('shackleford', 'shackelford') FROM DUAL;  
-------------
returns 2 

EDIT_DISTANCE_SIMILARITY Function

This function calculates the number of insertions, deletions or substations required to transform string-1 into string-2, and returns the Normalized value of the Edit Distance between two Strings. The value is typically between 0 (no match) and 100 (perfect match).�

Syntax

UTL_MATCH.EDIT_DISTANCE_SIMILARITY (
   s1  IN  VARCHAR2, 
   s2  IN  VARCHAR2) 
 RETURN PLS_INTEGER;�

Parameters

Table 256-4 EDIT_DISTANCE_SIMILARITY Function Parameters

Parameter Description

s1

The string to be transformed

s2

The string into which s1 is to be transformed


Examples

SELECT UTL_MATCH.EDIT_DISTANCE_SIMILARITY('shackleford', 'shackelford') FROM DUAL;
--------------
returns 82

JARO_WINKLER Function

This function calculates the measure of agreement between two strings.�

Syntax

UTL_MATCH.JARO_WINKLER (
   s1  IN  VARCHAR2, 
   s2  IN  VARCHAR2) 
 RETURN BINARY_DOUBLE;�

Parameters

Table 256-5 JARO_WINKLER Function Parameters

Parameter Description

s1

Input

s2

input


Examples

SELECT UTL_MATCH.JARO_WINKLER('shackleford', 'shackelford') FROM DUAL;
--------------
returns 9.818E-001

JARO_WINKLER_SIMILARITY Function

This function calculates the measure of agreement between two strings, and returns a score between 0 (no match) and 100 (perfect match).�

Syntax

UTL_MATCH.JARO_WINKLER (
   s1  IN  VARCHAR2, 
   s2  IN  VARCHAR2) 
 RETURN PLS_INTEGER;�

Parameters

Table 256-6 JARO_WINKLER Function Parameters

Parameter Description

s1

Input

s2

input


Examples

SELECT UTL_MATCH.JARO_WINKLER_SIMILARITY('shackleford', 'shackelford') FROM DUAL;
--------------
returns 98