writing simple statements. The database engine reads
those statements and determines how to satisfy them on the tables in
the database.</p>
        <p>SQL is the main practical advantage of relational database systems.
Rather than writing a computer program to find records of interest, the
relational system user can just type a query in a simple syntax, and
let the engine do the work. This gives users enormous flexibility; they
do not need to decide in advance what kind of searches they want to do,
and they