Re: [Phplib-users] nextid - how does it work?

[Layne W. <la...@dr...>]

> There are some instances where it is useful or even necessary to know 
> ahead
> of time what primary key will be assigned to a given record when it is
> inserted. This function provides one means of doing that.

Here are some other uses for nextid() from personal experience:

1. Reference IDs based on date in the format YYYYMMxxxx (where xxxx 
provides for enough IDs). At the beginning of each month I can set my 
counter to e.g. 2003070000 and increment from there, skipping unused 
200306xxxx IDs.
2. Non-primary keys. For instance, the primary key for an employee 
table is the SSN, but if I also want to know that I was the first 
employee, Fred was the second employee, etc. I need to keep another 
counter.
3. Force Unique IDs. MySQL's auto-increment feature creates an ID one 
greater than the largest ID currently in the table. If I create a new 
record and then delete it before another record is created, MySQL will 
reuse the ID. Occasionally I will duplicate table structures in two 
databases (one for editing, one for holding currently published data). 
MySQL's behavior eliminates any chance of data integrity when 
publishing newly edited data.

I'm sure there are more reasons out there...

Layne Weathers