Subject Re: how left() works in dbase 11 plus
From AGOSTINHO <agostinhoteixeira@yahoo.com>
Date Sun, 30 May 2021 23:38:23 -0400
Newsgroups dbase.getting-started

Dear Mervyn Bick thanks you for your help and support.

The Entryfield4 is where the users search clients in database.

This is how I have my clients.dbf query setup with a GRID on the form

this.CLIENTS1 = new QUERY(this)
   with (this.CLIENTS1)
      left = 4.0
      top = 24.0
      sql = 'select * from "C:\Users\HOME_PC\Desktop\dBASEtutorial\clients.dbf" where lower(customercode+name+address) like lower(:ag)'   params["ag"] = "%"
      active = true
   endwith

so whatever number the user type it will search for customer number, I use 4 digit for customer number.
In the same entryfield4 if the user type character instead he will get the customer  name or customer address.
This works perfect so far, just like a Google search.

Now  if the user want to add a customer to the database.
First he have to test if the number he wants to add  already exists in the database.
In old DBASE DOS I used to program the following

find &ccode
   yn=" "
   if .not. found() .or. eof()
    ?chr(7)
    @23,05 say 'Customer name not found   ,Add new Customer to the list? Y/N !'
    get yn
    read
    if upper(yn)="Y"
       if val(ccode)<99 .or. val(ccode)>9999
             wait "                  ACCEPT ONLY FOUR(4) DIGITS FOR CUSTOMER No. "      
             ccode="     "
             loop
      endif
      if val(ccode)>1 .and. val(ccode)<999
           if left(ccode,1)<>"0"
               wait "                  ACCEPT ONLY FOUR(4) DIGITS FOR CUSTOMER "                                     
               ccode="     "
               loop
           endif
      endif
      append blank
      replace code with ccode
   endif
endif

This is what I've done in my form to get the same result.

function ENTRYFIELD4_onKey(nChar, nPosition,bShift,bControl)
      form.clients1.params['ag'] = '%'+this.value+'%'
      form.clients1.requery()
                if form.entryfield4.value<9999 .and. form.clients1.rowset.endofset
                   if msgbox( "Add New Customer?", " ", 36 ) == 6
                       form.rowset.beginAppend()
                                 form.rowset.fields["code"].value = form.entryfield4.value
                                 form.rowset.save()
                        endif
                 endif
      return

Agostinho
Thanks

  




Mervyn Bick Wrote:

> On 2021/05/30 08:03, AGOSTINHO wrote:
 > > Dear group,
 > >
> > If I want to test an user's input in DBASE DOS I do somethng like this
 > > ?left(ccode,4)
 > >
> > I've tried it in this function but I get an error
 > > also need to make sure that the input are numbers only.
 > >
> > function ENTRYFIELD4_onKey(nChar, nPosition,bShift,bControl)
 > >        form.clients1.params['ag'] = '%'+this.value+'%'
 > >        form.clients1.requery()
 > >        if form.entryfield1.value.left(4)
 > >                    do something
 > >       endif
 > >       return
 >
> Error messages usually, but unfortunately not always, point to exactly
> what is wrong.  It does help though if you give us the wording of the
> error message.
 >
> Set the value property of entryfield4 to Integer.  This will ensure that
> the only digits can be entered.
 >
> Adding '%' to the start and end of the value will automatically convert
> the result to character so that the requery() will work properly.
 >
> The left() function only works with strings, not numbers.  You can test
> for a 4 digit number as follows.
 >
>       if form.entryfield4.value > 999 and form.entryfield4.value < 10000
 >          do something
 >          return
 >
> At present you onKey event handler requeries and fetches a new rowset as
> each digit is entered.  If you are not going to "do something" until you
> have entered 4 digits then the following may be a better option
 >
>
>     function ENTRYFIELD4_onKey(nChar, nPosition,bShift,bControl)
 >        if form.entryfield4.value > 999
 >           form.clients1.params['ag'] = '%'+this.value+'%'
 >           form.clients1.requery()
 >          do something
 >        endif
 >        return
 >
> This will requery as soon as the 4th digit is entered.  If you want to
> prevent further digits from being entered then add the 'and
> form.entryfield4.value < 10000' to the test or set the entryfield's
> picture property to'9999'.
 >
> Mervyn.
 >
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