optimization in C

in C, I work on a database (4 table).

    COPY FROM file ;
    SELECT, INSERT, UPDATE, DELETE for a result in the last                 table.
    COPY TO file ;

in the file, are stored 10000 informations.

-> It's slowly !!!
Can you help me for optimization this?

I didn't use Oid, trigger and function SQL.

Thanks.
Jerome.