IDS with INFORMIX-SQL Perform Screens:
Let's say I'm adding a new customer row with perform. I want to scan the customers drivers license and store that image along with the customers personal info. How is this accomplished?.. Later on, the customer returns and I query his personal info. Then I want to view the customers drivers license. How does perform know where to find and display that customers drivers license?
If you are using IDS 9.x or later, you have BLOB or CLOB blobs as well as BYTE and TEXT blobs. If you are using OnLine 4.00 or later (but prior to IUS 9.00), you will have BYTE and TEXT blobs only.
ISQL can more or less handle TEXT blobs; on command, it will launch the program of your choosing on a file containing the TEXT blob data, and will save the contents of that file back to the database when you complete the INSERT (Add) or UPDATE operation. ISQL will also display the first few lines of the TEXT blob on the screen.
ISQL can only partially handle BYTE blobs. It can run the program you designate on a file containing the value of the BYTE blob, but it cannot display the content of the file (which is not wholly unreasonable; it is/was designed for curses-based green-screen terminals, and they are not notorious for high quality colour bitmap graphics).
ISQL cannot handle BLOB or CLOB columns at all, AFAIK.
If you want to display the image of a driver's licence, you will have to decide how the image is scanned, stored, and displayed. While you might be able to launch a program to show the licence image on a bitmap screen, you're no longer strictly within ISQL. Similar comments apply to I4GL. Neither ISQL nor I4GL can truly display bitmap images.
(My first encounter with OnLine and BYTE/TEXT blobs was writing a demo application to display images of pictures from an I4GL program running on SunOS - for the UK 'Which 1990' computer show.)