Re: Using LIKE to define records in 4GL

> > brent@hypercom.co.nz (Brent Jackson) nattered on and on about: > > >We have no problems using LIKE, but it is forbidden to use the "RECORD LIKE > >table.*" and the "SELECT * FROM" constructs. It is the * that causes > >problems, rather than the LIKE. > > I seem to have missed the original question. What problems are you > specifically referring to here? The only problem I know of with using > LIKE constructs is in INPUT ARRAY navigation. The user can get stuck > on a line if the field they are currently in is a NOT NULL column in > the database. We work around this by using formonly screen fields > when necessary, althought this breaks the syscolval and syscolatt > funtionality completely. > > Are there other difficulties I should be aware of? Fourgen uses this > construct heavily in their program generator. The biggest problem, with it is in a maintenance situation. Here check it out. CREATE table tab ( a char(1), b char(1), c char(1)) DEFINE abc RECORD LIKE tab.* # So abc looks like: abc.a, abc.b, abc.c ..... SELECT * FROM tab INTO abc.*.... compile 4gl code.... ALTER TABLE tab ADD COLUMN d char(1) BEFORE column b run 4gl code.... (compiled on old schema) Your cursor is now doing: SELECT a, d, b, c INTO abc.a, abc.b, abc.c If you have made a habit of this, that's a lot of places to track it down and fix (at very least by recompiling). If you did DEFINE abc RECORD a char(1), b char(1), c char(1) AND your select statement did: SELECT a, b, c FROM tab INTO abc.* Then you are insulated - no matter what new columns are added your code will still work the way it was intended. So is it such a big sacrifice to have to type in the extra code? 1 minute now will save you hours down the road. cheers j. _____________________________________________________________________________ Jack Parker - Hewlett Packard, DMD/IS Boise, Idaho, USA jparker@hpbs3645.boi.hp.com _____________________________________________________________________________ "I'm with the IRS, I'm here to help you" _____________________________________________________________________________ Any opinions expressed herein are my own and not those of my employers. _____________________________________________________________________________