Basically correct. But you should also:
Use lock() / rlock() to avoid conflicts (two users trying to create the same PK-value at the same time).
Instead of closing the table, keep it open - this is much faster.if not used("ids")
use ids in 0
endif
select idsMake sure you return to the previously SELECTed area.
Instead of notifying the user that a specific sequence doesn't exist, you can create it.
A single parameter should be enough for most operations: the name of the sequence.
Here is my own version of the function:
FUNCTION SERIALNUMBER(tnSequence)
tnSequence = lower(tnSequence)
local lnSelect
lnSelect = select()
if used("serialnumber")
select serialnumber
else
select 0
use serialnumber
endif
set order to "sequence"
seek padr(tnSequence, len(sequence))
if not found()
append blank
replace sequence with tnSequence, nextnum with 1
endif
local lnReturnValue
if lock()
lnReturnValue = nextnum
replace nextnum with nextnum + 1
else
lnReturnValue = -1
endif
unlock
select (lnSelect)
return lnReturnValue
ENDFUNC
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
