Not able to update MySQL table using Oracle: Unknown column in 'where clause' {42S22,NativeErr = 1054}
by experience sometimes creating oracle tables by using ODBC produce errors.

so please try to do the following:


create the table manually on oracle db by using sql plus.
try to use capital letters for table and column names without double quotes (example: use TABLE_NAME not table_name or Table_Name) 
try to run your application to check if any errors appears. 


also in where clause you have to check it.
try:

WHERE SRC."INT_ID" = REC.MYSQL_INT_ID;


does it works?