doubts on the following code

// Create a filters array and define search filters for an Item search
var filters = new Array();

// filter by a specific customer (121) on the Pricing record
filters[0] = new nlobjSearchFilter('customer', 'pricing', 'is', '121');

// filter by a currency type (USA) on the Pricing record
filters[1] = new nlobjSearchFilter('currency', 'pricing', 'is', '1');

here the two filters...
does it mean that the system made a join operation between customer and pricing record( if so, how are they joined? or how the system does a matching between them? on which column)

// set search return columns for Pricing search
var columns = new Array();

// return data from pricelevel and unitprice fields on the Pricing record