When setting up the ODBC driver, it is important to set the 'Use Declare/Fetch' option. Set this option so that images are retrieved on demand. This is especially important when exporting images. If this option is not set, the ODBC driver will retrieve all the images from the database before saving them to disk, which consumes a lot of system memory. When this option is set, the ODBC driver retrieves the images on demand.
Another important setting is the 'Max Varchar' value. You should set his value to the size of the single largest image that you will retrieve from your database. E.g. if your database has 1000 images, and the largest image is less than 1 MB, you should set the 'Max Varchar' value to 1048576. If you attempt to retrieve images that exceed this 'Max Varchar' value, the ODBC driver will report a 'Variable length column overflow error' exception.
