SQL is a very powerful and flexible language. This article introduces the interactive SQL command line tool to run SQL statements on your IBM i.
By Tom Snyder
In this TechTip, we'll explore the functionality of the interactive SQL tool.
Library Lists and File Overrides
The SQL statements that you run from the command line use the library list of the session that you are signed onto; therefore, you can refer to the physical files by name and they will have the same reference as your F-specs. When you are initially trying out interactive SQL, I recommend that you copy a file into a test library and put that library on the top of your library list.
If you are working with a multiple-member file, you can execute an OVRDBF command at the command line before you call the STRSQL command. Before you execute any queries using the interactive SQL tool, I recommend that you execute an OVRDBF command for the file you will be working with and then DBU the file without a library or member reference to make sure you're working with the correct file and to double-check your overrides and library list.
OK, you have your test environment established and you're ready to go.
SQL Practical Example
For a practical example, let's suppose your accounting department set up a new product on the system with the correct code of 777, but the incorrect category of "Columbian." Some billing has already been performed, and the reports are showing the revenue in the wrong category. They have since corrected the code attributes, but the history still reflects the wrong code. (I know this never happens, but it's just for example purposes.)
You could write a program to do this, or you could do this more quickly by using interactive SQL.
Suppose you have the following simple BILLING file:
BILLING:
BACCT, Account
BDATE, Date
BDESC, Description
BAMT, Amount
BCODE, Code
BCAT, Category
| Account | Date | Description | Amount | Code | Category |
| 1 | 20081114 | Coffee Purchase Lb | 10.00 | 777 | Ethiopian |
| 1 | 20081114 | Coffee Purchase Lb | 10.00 | 777 | Columbian |
| 1 | 20081114 | Coffee Purchase Lb | 10.00 | 777 | Costa Rican |
| 1 | 20081114 | Cup Purchase | 5.00 | 222 | Travel Mug |
| 2 | 20080621 | Coffee Purchase Lb | 10.00 | 777 | Kenyan |
| 2 | 20080621 | Coffee Purchase Lb | 10.00 | 777 | Columbian |
| 3 | 20080812 | Coffee Purchase Lb | 10.00 | 777 | Hawaiian Kona |
| 3 | 20080812 | Coffee Purchase Lb | 10.00 | 777 | Columbian |
| 4 | 20081208 | Coffee Purchase Lb | 10.00 | 777 | Columbian |
| 4 | 20081208 | Coffee Purchase 5 Lb | 45.00 | 888 | Columbian |
For this example, you want to create a SELECT query to review the records that will be affected by the update. You can initially review the results of the report to tweak your SQL statement until you get the desired results. You could also present this report to the person who identified the problem to ensure that the correct records are being identified for update.
To view all of fields for all of the records in the BILLING file:
SELECT * FROM BILLING
To view only records of interest:
SELECT * FROM BILLING WHERE BCODE = 777 AND BCAT = 'Columbian'
The SELECT query for the records of interest will provide the following results:
| Account | Date | Description | Amount | Code | Category | ||||
| 1 | 20081114 | Coffee Purchase Lb | 10.00 | 777 | Columbian | ||||
| 2 | 20080621 | Coffee Purchase Lb | 10.00 | 777 | Columbian | ||||
| 3 | 20080812 | Coffee Purchase Lb | 10.00 | 777 | Columbian | ||||
| 4 |
Thomas Snyder has a diverse spectrum of programming experience encompassing IBM technologies, open source, Apple, and Microsoft and using these technologies with applications on the server, on the web, or on mobile devices. Tom has more than 20 years' experience as a software developer in various environments, primarily in RPG, Java, C#, and PHP. He holds certifications in Java from Sun and PHP from Zend. Prior to software development, Tom worked as a hardware engineer at Intel. He is a proud United States Naval Veteran Submariner who served aboard the USS Whale SSN638 submarine. Tom is the bestselling author of Advanced, Integrated RPG, which covers the latest programming techniques for RPG ILE and Java to use open-source technologies. His latest book, co-written with Vedish Shah, is Extract, Transform, and Load with SQL Server Integration Services. Originally from and currently residing in Scranton, Pennsylvania, Tom is currently involved in a mobile application startup company, JoltRabbit LLC.
MC Press books written by Thomas Snyder available now on the MC Press Bookstore.
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