Hi i am new to pega , so pls help me with example

does obj-open return multiple records in pega? i could see lot of posts on the internet suggesting obj-open returning  multiple records

-> as far as i could find .. it does not as we have to pass all the keys of the class instance to open , and all keys of the class instances are unique if i have K1,K2,K3 , the combination of keys are always unique 

example k1=1,k2=1,k3=1 , k1=1,k2=2,k2=2 , k1=1,k2=3,k3=3 --- that is combination of all the three keys k1,2,3 are always unique

or

if the class has only one key k1 it cannot have same value as its a primary key.

so i could not get create a scenario which returns multiple records using obj-open, pls guide me

***Edited by Moderator Marissa to update platform capability tags****