1. A computer implemented method for inventory management system comprising a plurality of products associated with Quick Reference (QR) codes, the method being capable of providing flexible and secure inventory management, the computer implemented method comprising: scanning the QR code of a product via a scanning device being operated by a user; receiving an input code from the user for the corresponding QR, assigning a value to the QR code such that the value is taken from a relational database, storing the said user input code in the relational database; associating the said user input code with the said QR code in the inventory management system, wherein such association of the input code enables the user to locate various products in the inventory by searching with the said user input code rather than the QR code; prompting the user to change the assigned value to the QR code via a logic engine capable of linking or delinking the user input code with the QR code.