Skip to main content

FoxPro Tip: Be Aware of Disappearing Index files (IDX)

There's still a lot of older FoxPro code that relies on the old IDX file - especially for temporary indexes that only need to be created on an as needed basis.

Now, you can create indexes on temporary cursors just as with regular tables but there's a trick to be aware of.

When you create an IDX file on a DBF file that physically exists , the IDX file will still be there after you close the table.

However, if you create an IDX file on a temporary cursor, as soon as you do anything that may close the index, the IDX file is instantly deleted.

Try it:
USE HOME(2)+"DATA\CUSTOMER"
INDEX on customer.city TO t
DIR t.idx && the file is there
SET INDEX TO
DIR t.idx && the file is STILL there
SELECT * FROM customer WHERE region ='WA' INTO CURSOR wacust
BROWSE
INDEX on city TO wat
DIR wat.idx && the file is there
SET INDEX TO wat.idx && Error file does not exist

Why ? Because the SET INDEX TO statement clears the previous index and attempts to reset it. But when it clears it, FoxPro recognizes that it is a temporary cursor and thus deletes the index.

The solution?

issue a SET INDEX TO ADDITIVE and that should keep it there.

Comments

Post a Comment

Popular posts from this blog

Merry Christmas

Whether you celebrate now, have already celebrated your past holiday, are planning to, or not, I hope you find yourself surrounded by family and those you love during this holiday season and are able to remember fondly those who are not with you. We often find ourselves buried in work, or too distracted by other problems, to share and remember a few moments with those closest to us. So many of us are separated by huge distances, we often find it easier to focus on those who are out of arm's reach yet so easy to connect with online, instead of those who are right beside us. So do yourself a favour, put down the keyboard (stylus, mouse, etc) and spend that time. I know I will. Merry Christmas. Powered by ScribeFire .
4 comments
Read more

Programmers vs. Developers vs. Architects

I received an email this morning from Brandon Savage 's newsletter. Brandon's a PHP guru (works at Mozilla) but his newsletter and books have some great overall perspectives for developers of all languages. However, this last one (What's the difference between developers and architects?) kind of rubs me the wrong way. Either that, or I've just missed the natural inflation of job descriptions. (maybe, it's like the change in terminology between Garbage man and Waste Engineer or Secretary and Office Administrator) So maybe it's just me - but I think there's still a big difference between Programmer, Developer and then of course, architect. The key thing here is that every role has a different perspective and every one of those perspectives has value. The original MSF create roles like Product Manager, Program Manager, Developer, Tester, etc - so every concept may pigeon hole people into different roles. But the statements Brandon makes are often distinction...
11 comments
Read more

From Writing to AI: the pattern repeats itself

When I was ten years old, my dad bought a computer and, thanks to an advertising supplement in a Superman comic I read, it was a TRS-80. A month later, he dragged the entire family (my mom and brother were not the most enthusiastic) to a class at Radio Shack teaching how to use microcomputers. At the time, I understood why my mom wasn’t that excited: the computer was yet another gadget in the house. But today I find it fascinating. My mother went to Vassar in the 50s. She learned how to type — not a common skill at the time — but it opened doors. Her ability to communicate effectively led her to a career in adult education and later communications work with the CBC (Canadian Broadcasting Corporation). This isn’t a nostalgia post. Today, the ability to use artificial intelligence, be it through Copilot or simply writing the right prompt, is becoming a critical skill. But is it really that novel? In the 1500s and 1600s, the printing press gradually made reading accessible beyond cler...
Post a Comment
Read more