Is it possible to access a row in a datatable in constant time?

[=?Utf-8?B?UnlhbiBBbmRydXM=?=]

Is there a way to configure\create a datatable (strongly typed or untyped)
that can have a row accessed in constant time if you are searching on the
primary key?

If there isn't a way, then what is the quickest way to access a row when
using datatables?

Thanks,

Ryan

[AlexS]

I don't believe it is possible to guarantee processing time in Windows
environment.

Because search time depends on data size you can't guarantee constant time
when searching either. You can hope to have more or less same time when your
data has fixed size. But there will be no guarantee.

I believe fastest way is by row index. But also no guarantee for processing
time.
"Ryan Andrus" <Ry********@discussions.microsoft.comwrote in message
news:97**********************************@microsof t.com...

Is there a way to configure\create a datatable (strongly typed or untyped)
that can have a row accessed in constant time if you are searching on the
primary key?

If there isn't a way, then what is the quickest way to access a row when
using datatables?

Thanks,

Ryan

[=?Utf-8?B?UnlhbiBBbmRydXM=?=]

I don't believe it is possible to guarantee processing time in Windows

environment.

arrays don't provide constant access time? that seems wrong to me. I think
it is possible, if nothing else you could do it in unmanaged C++ but I would
be very supprised if arrays didn't offer constant time access.

I believe fastest way is by row index. But also no guarantee for processing
time.

can someone please at least speak to the Big O analasys of this access or
point me to what algorythm is used so that I can calculate it. Is it a b
tree, linked list, etc...

thanks
"AlexS" wrote:

I don't believe it is possible to guarantee processing time in Windows
environment.

Because search time depends on data size you can't guarantee constant time
when searching either. You can hope to have more or less same time when your
data has fixed size. But there will be no guarantee.

I believe fastest way is by row index. But also no guarantee for processing
time.
"Ryan Andrus" <Ry********@discussions.microsoft.comwrote in message
news:97**********************************@microsof t.com...

Is there a way to configure\create a datatable (strongly typed or untyped)
that can have a row accessed in constant time if you are searching on the
primary key?

If there isn't a way, then what is the quickest way to access a row when
using datatables?

Thanks,

Ryan

[AlexS]

You need to factor in other processes and threads, OS kernel etc.. Any
thread could be interrupted at arbitrary moment.
"Ryan Andrus" <Ry********@discussions.microsoft.comwrote in message
news:34**********************************@microsof t.com...

>I don't believe it is possible to guarantee processing time in Windows
environment.

arrays don't provide constant access time? that seems wrong to me. I think
it is possible, if nothing else you could do it in unmanaged C++ but I
would
be very supprised if arrays didn't offer constant time access.

>I believe fastest way is by row index. But also no guarantee for
processing
time.

can someone please at least speak to the Big O analasys of this access or
point me to what algorythm is used so that I can calculate it. Is it a b
tree, linked list, etc...

thanks
"AlexS" wrote:

>I don't believe it is possible to guarantee processing time in Windows
environment.

Because search time depends on data size you can't guarantee constant
time
when searching either. You can hope to have more or less same time when
your
data has fixed size. But there will be no guarantee.

I believe fastest way is by row index. But also no guarantee for
processing
time.
"Ryan Andrus" <Ry********@discussions.microsoft.comwrote in message
news:97**********************************@microso ft.com...

Is there a way to configure\create a datatable (strongly typed or
untyped)
that can have a row accessed in constant time if you are searching on
the
primary key?

If there isn't a way, then what is the quickest way to access a row
when
using datatables?

Thanks,

Ryan

[PhilipDaniels]

On Fri, 13 Jul 2007 08:14:04 -0700, Ryan Andrus
<Ry********@discussions.microsoft.comwrote:

>can someone please at least speak to the Big O analasys of this access or
point me to what algorythm is used so that I can calculate it. Is it a b
tree, linked list, etc...

Are you familiar with Lutz Roeder's Reflector? It allows you to
decompile assemblies, including the supplied .Net ones, and examine
the code. The DataRowCollection is implemented in terms of a red-black
tree.
--
Philip Daniels

[=?Utf-8?B?UnlhbiBBbmRydXM=?=]

Thanks Philip,

So, as far as you know is DataTable.Row[<index>]

The quickest access method resulting in O(log n) complexity?

"Ph***********@foo.com" wrote:

On Fri, 13 Jul 2007 08:14:04 -0700, Ryan Andrus
<Ry********@discussions.microsoft.comwrote:

can someone please at least speak to the Big O analasys of this access or
point me to what algorythm is used so that I can calculate it. Is it a b
tree, linked list, etc...

Are you familiar with Lutz Roeder's Reflector? It allows you to
decompile assemblies, including the supplied .Net ones, and examine
the code. The DataRowCollection is implemented in terms of a red-black
tree.
--
Philip Daniels