Re: how to convert datatypes ?

Michael, Before I go any further, let me point out that I cannot claim to be an unbiassed observer on this, but I do have what may be some useful information... You also do not specify which Informix language you are using, which always makes it more difficult to give an appropriate response. I'm going to assume that you are referring to I4GL, but you might be referring to SPL (Stored Procedure Language), in which case some of the comments are somewhat different, but I go through the differences at the end of this message. >From: "Michael Agbaglo" <byteshif@cs.tu-berlin.de> >Date: 1 Dec 1996 19:10:15 GMT >X-Informix-List-Id: <news.31081> > >First I had to write extra code because this amateur programmers a informix >weren't able to implement select ... into ... order by. Pardon? As far as I know you can do: DECLARE c_order CURSOR FOR SELECT ... INTO ... FROM ... ORDER BY ... I can certainly get that to work for me, though I suppose it might not work for you for some very peculiar reason -- you'd have to give a detailed example to demonstrate that. Of course, if you've prepared the SELECT statement, then you have to omit the INTO part from the PREPARE and DECLARE and specify it in the FOREACH instead, but there are sound reasons for that. >Then I browsed the manuals for 'convert' w/o success. When I do a >LET Stmt = VARCHAR( foo ); >it thinks VARCHAR is a procedure --- Arrgh! I4GL converts implicitly -- it doesn't need casts as it will do the conversion for you. So, if 'foo' is any type of variable except a blob, and Stmt is a VARCHAR, then: LET Stmt = foo; will do the relevant conversion for you. No need to put in explicit conversions at all. >Then I browsed for string functions - nothing, no MID, LEFT, RIGHT... Well, these are mainly a question of what you're used to. I've not used those functions since I left BASIC behind, so I'd not go looking for them. Let's take LEFT(), first. I assume you want to write something like: LET substr = LEFT(string, len) In I4GL, you do that with: LET substr = string[1, len] Dealing with RIGHT() next, I assume you want to write something like: LET substr = RIGHT(string, len) In I4GL, you do that with something based on: LET substr = string[LENGTH(string)-len+1, LENGTH(string)] And assuming that MID() should be used something like: LET substr = MID(string, start, len) In I4GL, you do that with: LET substr = string[start, start+len-1] >Have they been exhausted by implementing 'LENGTH' ? No. >If someone what's to implement a shit app - forget it Informix already did >it ! I disagree whole-heartedly. Go to some other language like Perl, and see whether there is a LEFT(), RIGHT() or MID() function built-in. The answer is "No, it isn't". But that doesn't mean that it is impossible to achieve the same effect, nor that it is impossible write a set of functions called LEFT(), RIGHT() and MID() which do the same as the functions you are used to using in some other language. Similarly, in I4GL, there are different ways of achieving the same result, and nothing to stop you writing a set of functions which do what I did in a single statement. Now, what would be different if you are slamming SPL instead of I4GL? The implicit conversions act the same in SPL as in I4GL. And you can use cursors on ordered data in SPL. There isn't any dynamic SQL in SPL to confuse the issue. OTOH, the obvious problem is that SPL does not allow variable substring operations, so you cannot write the code I wrote above in SPL. That is a serious problem, but it will be fixed (directly or indirectly) by the Informix Universal Server, due to be released before the end of this year. Yours, Jonathan Leffler (johnl@informix.com) #include <disclaimer.h>