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> I haven't seen anything yet that talks explicitly about when
> to use the Name attribute and when to use the Scope
> attribute. There have been a number of threads around
> whether to single thread updates to a single table.
>
> For example, lets say that I read from a table in two
> programs and write/delete from a third. For this example,
> lets say I want to single thread all writes. To do this,
> would you use scope="application" type="readonly" to lock
> the two read queries and scope="application" type="exclusive"
> around the write or would replace the scope attribute in both
> with something like name="databasename.tablename"?
First of all... Why in lord's name would you want to single thread
your DB access? You use an RDBMS like Access, SQL Server, or
whatever because your DB handles all the locking & concurrency issues
for you. I can think of a few VERY limited cases where you might
need to single thread access (perhaps in some sort of status tracking
or *something*). If I ever ran into a situation like that, I'd think
LONG & HARD about how to get around the problem without single
threading the DB. That's just ASKING for performance nightmares...
In any case, if you did need to lock your DB for one particular
table, then you would use a named lock with something like
name="database.table" or whatever.
Here's the skinny on when to use scope & when to use name for CFLOCK:
If you're accessing a shared CF variable in the session, application,
or server scope, then you should use a scoped lock of the appropriate
scope. You *shouldn't* access more than one scope within a single
lock, tho I suspect you could access session in an application lock
and application & session in a server lock without killing the
server. I would think that if automatic checking is enabled, it
would probably disallow that activity. I certainly wouldn't code
anything to use it.
For basically everything else, you use named locks. When you're
controlling access to anything that falls outside of the three CF
shared scopes -- mostly "outside world" type of stuff -- scope
doesn't work.
Examples:
You have a non-thread safe CFX tag. You should use a lock that is
the name of the tag around all accesses to it.
Your DB example above is another valid example, tho I'm not sure why
you'd want to do that.
Hopefully that's at least a little clearer than mud...
Best regards,
Zac Bedell
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