Database Mapping app performance issue. Any suggestion ?

Question

Hi all,

I'm involve on a project which going to map database record from one DBMS into another DBMS. When the record number is small, there no problem, but now as the record number grow and grow rapidly,, there a performance issue.

here my situation,

i'd like to append (and mapping) several record from one DBMS table into another DBMS table. Before append the record, user has capability to map a record into an SQL Expression. My problem is, before is do the append ( and mapping ) processes, i need to validate the expression againts backend.
So in this case i need to validate an expression againts all record on single table from DBMS,, or is there any other way to validate those SQL expression ?
Or any suggestion for me ?

FYI, for appending and mapping 10 record of 18 columns table into 14 columns of table,, it took about 20 second to complete.
prety long time for me. The process need to verify SQL expression from source table, this verify process i've described above, and my test table contain only 70000 records, which i think a small number of record.


any suggestion will be appraciated.

thx.