![nullind allows in null in rpg variables and fields](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT4L03pi1i_Mb2FfZx06UhHPUmLXadO0Hox5uzQMrwlZT47L4lMiWtDcjnKCchZMJXIplPVO477bdGW7PEsswv8yhU-lPlMuNc9oB9ieOVCMEQUrTLQOeSCbRZenrYJDd-GNEGHKyWh4ty/s200/rpg.png)
Null is a concept that RPG programmers are going to have to learn. Generations of RPG programmers have used a blank or zero in a variable to denote that it is not used or its value is not given. Null, in the simplest terms, means nothing, and if there is not a value for variable then null would be the ideal value to give it. If I had used a blank instead how am I to know, later, if blank is a valid value or is it being used to denote there is no value?
While null values can be found DDS files and SQL tables, it was not until IBM i 7.3 that I could code variables within my RPG programs that could be null.