OpenEuphoria

RE: Database key wildcard search

• Posted by Matthew Lewis <matthewwalkerlewis at YAHOO.COM> Dec 18, 2001
• 562 views

void wrote:
> Is it possible to search a record with a partial key (key with 
> wildcards).
> 
> now we have:
> rec = db_find_key("find_this_key")
> 
> a function like this would be very useful:
> rec = db_find_key_wildc("find_th?s_???")
> 
> It should be possible to build such a function, but key_pointer 
> structure is a bit too complicated for me, can someone offer some help?
> 
> (I think an integer 'starting_rec' is needed to do multiple searches:
> rec = db_find_key_wildc("find_th?s_???", starting_rec)

You can almost do this:

rec = db_find_key("find_th")

should return a negative value (assuming it doesn't exist).  You can 
then start looking at records starting at the absolute value of rec:

-- Begin code

include wildcard.e

function wildkey( sequence wc, sequence wcfull )
    atom rec, found, size
    found = 0
    size = db_table_size()
    rec = db_find_key( wc )
    if rec > 0 then
      return rec
    else
        rec = -rec
        if rec > size then return 0 end if
        key = db_key( rec )
        while match(wc,key) = 1 do
            if wildcard_match( wc_full, key ) = 1 then 
                return rec 
            end if
            rec += 1
            if rec > size then return 0 end if
            key = db_key( rec )
        end while
    end if
    return 0
end function

? wildkey( "find_th", "find_th?s_???" )
-- End code

wc is the search string up to the first wildcard, and wc is the full 
wildcard.

Matt Lewis