METHOD AND APPARATUS FOR SEARCHING DATABASE COMPONENT FILES TO RETRIEVE INFORMATION FROM MODIFIED FILES

Each database component file contains information regarding the text contained in the source file which enables the user to quickly determine the frequency of occurrence of the specified text and the location of the specified text in the source file. For each textual word (referred to herein as a "symbol") an entry in the database file is provided containing symbol information. The symbol information comprises the symbol name, symbol type and line number in the source file where the symbol is located. Line indentification information is also provided which contains the line numbers in the source file and corresponding line lengths and hash values which are computed from the contents of the lines of the text in the source file. Before a line of text identified in a query is displayed to the user indicating a result of the query, the line identification information provides the means to verify that the line of text identified in the symbol information is the same line of text contained in the source file. The hash value and line length corresponding to the line text is compared to a line length and hash value computed for the text retrieved from the source file. If the computed line length and hash value does not match the line length and hash value contained in the line identification information, the text does not match the database reference because the source file has been changed subsequent to the generation of the database. Thus, the problems that arise because the source file version does not match the version of the database component file is prevented.