So far, you have seen how to retrieve and add data to the database. However, suppose you would like to modify existing database rows. To modify data, you would use the UPDATE SQL statement. A simplified version of the syntax of the UPDATE statement looks like the code in Listing 3.3.
UPDATE table_name SET column_name = expression WHERE search_conditions
The specific example in Listing 3.4 explains the syntax quite well. After the statement in Listing 3.4 is executed against the data source, any employee with last name of “Peacock” and first name of “Margaret” as specified by the WHERE clause will be changed to “Hogue” as specified by the SET clause of ...