Remember that iconic scene in "All the President's Men" where hours tick by at the Library of Congress as reporters Woodward and Bernstein flip through mounting piles of index cards, each one memorializing a book requested by the White House?Chances are if Post reporters need that same information today, it's kept in an Excel spreadsheet that can be sorted, searched and alphabetized in a matter of seconds.Electronic databases are making it possible for journalists to analyze and present information that previously would have overwhelmed the limits of human patience.