Try this:
If you are using a table handler in MySQL that doesn't support transactions,
you must use LOCK TABLES if you want to ensure that no other thread comes
between a SELECT and an UPDATE. The example shown below requires LOCK TABLES
in order to execute safely:
mysql> LOCK TABLES trans READ, customer WRITE;
mysql> select sum(value) from trans where customer_id= some_id;
mysql> update customer set total_value=sum_from_previous_statement
where customer_id=some_id;
mysql> UNLOCK TABLES;
Without LOCK TABLES, there is a chance that another thread might insert a
new row in the trans table between execution of the SELECT and UPDATE
statements.
From:
http://www.mysql.com/documentation/mysql/bychapter/manual_Reference.html#LOC
K_TABLES
----- Original Message -----
From: "Hayan Al Mamoun" <[EMAIL PROTECTED]>
To: "MYSQL MAILING LIST (E-mail)" <[EMAIL PROTECTED]>
Sent: Monday, January 28, 2002 7:21 AM
Subject: Table Lock
> Hi, Is there a way to lock a table so that only one user can change it and
> then unlockit?
> I need to do this coz I want visitors to retrieve some values from a
> database but each value must be retrieved only by one user and then marked
> up to be expired, so I don't want two users to retrieve the same value
> Any suggestions
>
> Best Regards
> Hayan
>
>
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