Michael Kraus wrote:
G'day again...
Actually, I want the PID for neither of the reasons you've said. Rather,
I'm using the PID and the date/time as a unique identifier to a database
row. The main contents of the row could occur more than once in the
table I'm working with - however we want to link this exact row with
rows in other tables in the database. Initially I thought about using
the date/time as an identifier (which I was storing anyway), but
remembered that two instances of the script could be running
concurrently, so decided to incorporate the PID to ensure uniqueness.
If your database can't hand you a unique ID for a row of a table then
find another one. Doesn't MySQL have autoincrement fields which do
this:
CREATE TABLE t (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
data VARCHAR(100));
INSERT INTO t (id, data) VALUES (NULL, 'data');
where the NULL value results in the insertion of a unique number one
greater than any other value in that field?
Note that there's no race condition, as if both clients hand up NULL
simultaneously the DB server will assign a value to one client's insert
and then the other client's insert.
Cheers,
Glen
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