Model Driven Development (MDD) approach is often used to model application data and behavior by a Platform Independent Model (PIM) and to generate Platform Specific Models (PSMs) and even the source code by model transformations. However, these transformations usually omit constraints of the binary association multiplicities, especially the source class optionality constraint. This paper is an extended version of the paper ’Transformation of Special Multiplicity Constraints - Comparison of Possible Realizations’ presented at MDASD workshop at the FedCSIS 2012 conference. In this paper, we summarize the process of the transformation of a binary association from a PIM into a PSM for relational databases. We suggest several possible realizations of the source class optionality constraint to encourage the automatically transformation and discuss their advantages and disadvantages.We also provide experimental comparison of our suggested realizations to the common realization where this constraint is omitted.