What is Fuzzy Search & how to implement Fuzzy Search Technique for a Report Program using AMDP Class ?

[patil477pavan]

Introduction:

What is Fuzzy Search ? 

• A technique of finding the strings that match a pattern approximately (rather than exactly).


• A fault-tolerant search, which returns records even if the search term contains typos or additional/missing characters.


• Example: Typing ‘Wether’ in Google will also return a list of hits corresponding to ‘Weather/Whether’.


• The below figure gives us the clear idea.

Fig: Google (Source)

Fuzzy Search in SAP HANA:

• Can be applied in the WHERE clause of a SELECT statement using the function ‘CONTAINS’ with the option ‘FUZZY’


• SELECT * FROM <table_name> WHERE CONTAINS (<column_name>, <search_string>, FUZZY(x) ).


• <table_name> can be name of a column table, attribute view or a SQL view created with the CREATE VIEW statement


• FUZZY(x) specifies the degree of accuracy required between the strings used in comparison (<column_name> and <search_string>)


• ‘x’ in FUZZY(x) is called a fuzzy factor and can have values between 0 and 1.

Key Points:

• If only FUZZY is specified, it takes the value of x as 0.8


• If FUZZY(x)/FUZZY is not provided, an exact match is searched.


• CONTAINS function can also be used in a SELECT query with JOIN.


• 0 being least accuracy and 1 being highest accuracy.

What is AMDP Class ? 

• An AMDP Class is a global class existing in the class library with a tag interface IF_AMDP_MARKER_HDB (to indicate AMDP classes for the HANA Database Server)


• Can contain both regular methods and AMDP methods


• A method is indicated as an AMDP method in the implementation section of the class using the addition BY DATABASE PROCEDURE in the METHOD statement


• Can only be created using ADT.


• An AMDP method is called in an ABAP program in the same way as any other ABAP Objects method.

How to implement Fuzzy Search using AMDP Class ? 

Custom Table (ZSCARR) created as a part of this blog post and maintained the entries as shown in the below figures.

Simple Use Case:

Suppose , you have 100000's of record and you need to join multiple tables and fetch the output/data accordingly and the end user just wants to see the probable output based on the input provided by him. In this case , Fuzzy Search Technique comes handy.

• AMDP Class with Fuzzy Technique:

Fuzzy Search AMDP Class

• Consuming AMDP Class in Report Program:

Fuzzy Search Report Program

Selection Screen:

• Output when Fuzzy is  0.1

• Output when Fuzzy is  0.5

• Output when Fuzzy is  1

Summary:

• Fuzzy Search is a technique of finding strings that match a pattern approximately (rather than exactly).


• Fuzzy Search in SAP HANA makes use of two functions – CONTAINS() which performs search on strings and SCORE() which returns fuzzy score.