Mike Larsen
-
Guru: Creating A Web Service With Basic Authentication
August 12, 2024 Mike Larsen
I have been working with web services for many years, and I usually use IBM’s IWS (Integrated Web Service) tool to create them. The tool provides a wizard-based interface that allows me to quickly create a web service from an RPG program. Recently, I created a web service that uses basic authentication, and I want to share my experience.
I am assuming that you are already familiar with creating a web server and a web service, so I am just going to show the steps that need to be taken to add basic authentication functionality. If you would like me …
Read more -
Guru: Parsing JSON That Has Spaces In The Key
July 8, 2024 Mike Larsen
One of my favorite tasks is working with APIs. I’ve worked with many APIs over the years, and some introduce unique challenges that must be overcome. Recently, I worked on a project where I was to consume a REST API that provided a JSON payload. While that seems straight forward, I quickly discovered a challenge.
The JSON payload had keys that have spaces in them (Figure 1). That may be considered bad practice, but I still needed to figure out how I could parse it correctly. Having never seen JSON like this before, I started with a Google search. I …
Read more -
Guru: Partitioning Result Sets Using SQL
November 27, 2023 Mike Larsen
While working on a project recently, I needed to retrieve attributes of an item. While that sounds like a simple task, there was a twist. While reviewing the contents of the item master table, I noticed there could be multiple rows for the same item and each row was active and valid from a business perspective.
I won’t get into the business end of it, but my goal was to return the most recent iteration of the item for further processing in the program. After doing some research and trying some potential solutions, I came across the SQL partition by …
Read more -
Guru: Comparing IFS Directories Using SQL
June 19, 2023 Mike Larsen
I use SQL almost every day at my job. It may be just a query in ACS, or it may be embedded SQL in an RPG program. A few days ago, I needed to compare the contents of one IFS directory to another. Combining a few different table functions, I was able to develop a nice solution.
Note: The code for this article can be downloaded here.
In this example, I have a directory that has five text files in it. I have a second directory that has three text files in it, and they are the same documents …
Read more -
Guru: String Manipulation Using SQL
October 24, 2022 Mike Larsen
Recently, I was working with an employee file where first and last name were concatenated with a comma separator. A requirement of the project was to parse the name and populate a different table where first and last name are separate columns. I won’t address the design of the employee file, but I will show how I completed the request.
In Figure 1, I use the position string function via SQL to extract the first name.
Figure 1. Extract first name
In this example, I use the trim, substring, and posstr functions to position to the first …
Read more -
Guru: Regular Expressions, Part 2
August 15, 2022 Mike Larsen
In the first part of this series, I showed how to replace characters in a string using SQL and regular expressions. This time, I’ll show other regular expressions that are available for us to use. The regular expression functions I’ll show are REGEXP_COUNT and REGEXP_LIKE and the examples come from production programs that I’ve recently implemented.
In the first example (Figure 1), I want to get a count of the number of occurrences of a pattern within a string. To make this more interesting, I’m searching for two different patterns within a sting. To accomplish this objective, I used …
Read more -
Guru: Regular Expressions, Part 1
July 25, 2022 Mike Larsen
In the first part of this series, I will show how to replace characters in a string using SQL and regular expressions. I know I can replace characters using RPG or SQL, and they work great, but there are some cases where I find using regular expressions is a bit easier.
For the examples I’ll show, I’m using the REGEXP_REPLACE function. REGEXP_REPLACE allows me to search for a particular value within a string and replace it with another value.
In the first example (Figure 1), I want to search a string that has both letters and digits and I want …
Read more -
Guru: Debugging SQL Stored Procedures With ACS
April 11, 2022 Mike Larsen
I use Access Client Solutions (ACS) daily to help with different tasks. I’m usually running SQL scripts or working with the IFS, but recently I was asked if there was a way to debug SQL stored procedures using ACS. More specifically, they were looking for a way that a “non-IBM i” person can debug SQL stored procedures on IBM i.
After browsing the various menus in Run SQL Scripts in ACS, I found a system debugger. I had seen the system debugger before, but never took the time to explore it further. With this new request in mind, I decided …
Read more -
Guru: Creating PDF Documents With Python
July 27, 2020 Mike Larsen
I’m often asked to create reports for my business partners. The format of the report depends on who made the request. If the financial team made the request, I may produce an Excel file. The CEO may want to report quarterly sales to their shareholders. In that case, I may produce a PDF using the company letterhead.
In a prior article, I showed how to create Excel files using Db2 tables. Now I’m going to show how to create PDF documents using Db2 tables.
This story contains code, which you can download here.
I always start by making …
Read more -
Guru: Calling RPG Programs From Python, Part 2
April 27, 2020 Mike Larsen
In Calling RPG Programs From Python, Part 1, I showed how to call an RPG program from a Python script passing single string parameters as input and output. In the second part of this series, I’ll make the process a little more robust by passing a data structure to the RPG program.
The first part of the Python script (shown in the first piece of code below) imports the itoolkit modules and assigns them to local names. Next, I set up the first command that adds a library list entry to where the RPG object resides.
from itoolkit import
… Read more