1. A software configuration management system managing a source file for making up a software product and a software component that is a constituent element of the source file, the software configuration management system comprising: a software component database constructed at least in part of storage hardware and configured to store the software component in correspondence with a tree node that manages a software product as a tree structure and that makes up the tree structure; a software component database management unit constructed at least in part of at least one of a hardware processor and circuitry, and configured to store a software component/product correspondence table which is a piece of information that indicates the relationship between a software component and a software product including the software component for all the software components stored in the software component database, and to store update information which is a piece of information regarding an update for a software component stored in the software component database, the update performed on the basis of an update for a software product; a software product management unit constructed at least in part of at least one of a hardware processor and circuitry, and configured to store a plurality of software products created by combining software components stored in the software component database, and to store software component/file correspondence information which is a piece of information that indicates the relationship between a software component included in the software product and a source file for each of the plurality of software products stored in the software product management unit; a database operation interface unit constructed at least in part of at least one of a hardware processor and circuitry, and configured to receive an instruction from an external software component database management client computer, and to operate the software component database management unit according to the instruction; a product operation interface unit constructed at least in part of at least one of a hardware processor and circuitry, and configured to receive an instruction from an external software product operation client computer, and to operate the software product management unit according to the instruction; a synchronization unit constructed at least in part of at least one of a hardware processor and circuitry, and configured to commit a modification of a software component stored in the software component database to a software product stored in the software product management unit, or commit a modification of a software product stored in the software product management unit to a software component stored in the software component database and other software products stored in the software product management unit, based on the software component/product correspondence table and the software component/file correspondence information according to an instruction from the software component database management client computer or the software product operation client computer; and a correspondence table update unit constructed at least in part of at least one of a hardware processor and circuitry, and configured to update the software components stored in the software component database, the software component/product correspondence table, the update information, and the software component/file correspondence information in response to an instruction from the software component database management client computer; wherein the synchronization unit is configured to, upon receiving an instruction from the software product operation client computer to commit a modification of a source file of a software product stored in the software product management unit into a software component stored in the software component database, detect a software component corresponding to the modified portion of the source file by searching the software component/file correspondence information, detect all of software products including the detected software component among software components stored in the software component database by searching the software component/product correspondence table, and commit the modification of the source file into a software component included in the detected software product; and wherein the synchronization unit is configured to, upon receiving an instruction from the software product operation client computer to commit a modification of a source file of a software product stored in the software product management unit into other software products stored in the software product management unit, detect a software component corresponding to the modified portion of the source file by searching the software component/file correspondence information, detect all of software products including the detected software component among software products stored in the software product management unit by searching the software component/product correspondence table, and commit the modification of the source file into a software component included in the detected software product.