System and method of decomposition of multiple items into the same table-column pair

A system and computer-based method is provided for decomposing and storing content of a markup based document into a relational database. For a schema of a markup based document a user identifies multiple items mapping into a same database table-column pair and associates a rowset to each such item and a corresponding database table. Next, the user creates a mapping document based on the schema of the markup based document with rowset-specific mapping annotations defining mapping of the items into columns of the rowsets. Decomposition of each item into a corresponding rowset column is accomplished by collecting the item content from the markup based document and storing it in the corresponding rowset column, for later storage in a database table.