A method, system, and computer program product for implementing a multi-column/multi-row constraint. Lock techniques prevent access collisions even when two or more concurrently running software applications are attempting to insert rows into the same relational database table (subject to the same multi-column/multi-row constraints). The method commences by receiving (e.g., from a first process) a first row to be inserted into a relational database table where the row comprises at least two constrained columns corresponding to the multi-column/multi-row constraint, then receiving (e.g., from a second process) a second row to be inserted into the same table. Using column locks, the method recognizes the potential for conflicting row insertions, and manages locks to prevent conflicting access grants to the two constrained columns of the existing database table. The evaluation of the multi-column/multi-row constraint is performed over the first row to be inserted and a row or rows of the relational database table.