ISQL is very useful for running interactive SQL statements. As an option, it allows creating and executing scripts to automate certain operations. These scripts can be used for running DDL statements (Data Definition Language: create table, create index, alter table, etc.) and DML statements (Data Manipulation Language: insert, update, etc.). DML statements can become quite large if they must insert or update every record in a large table. ISQL is not intended for massive data load operations which require a large number of Insert statements.
FairCom provides tools that are more appropriate for manipulating large numbers of records: