Go Up to Using the Data Definition Guide
You can use
isql to interactively create, update, and drop metadata, or you can input a file to
isql that contains data definition statements, which is then executed by
isql without prompting the user. It is usually preferable to use a data definition file because it is easier to modify the file than to retype a series of individual SQL statements, and the file provides a record of the changes made to the database.
isql interface can be convenient for simple changes to existing data, or for querying the database and displaying the results. You can also use the interactive interface as a learning tool. By creating one or more sample databases, you can quickly become more familiar with InterBase.