Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.
Dim DT As New DataTable
DT.Columns.Add( "Price", GetType(System. Int32))
DT.Columns.Add( "ID", GetType(System. Int32))
DT.Columns.Add( "Vol", GetType(System. Int32))
Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChange s()
3  4888 
fniles,
No, I don't believe you can add an index to a datatable.
Keep in mind that datasets/datatables are not the same as an in-memory sql
database and trying to treat them as such will only lead to frustration.
Having said that, if you need an index for performance while selecting, you
might look into the dataview and its find methods. It will index on whatever
you set as its sort column.
Kerry Moorman
"fniles" wrote:
Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.
Dim DT As New DataTable
DT.Columns.Add( "Price", GetType(System. Int32))
DT.Columns.Add( "ID", GetType(System. Int32))
DT.Columns.Add( "Vol", GetType(System. Int32))
Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChange s()
On Sep 18, 8:41*am, "fniles" <fni...@pfmail. comwrote:
Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.
Dim DT As New DataTable
DT.Columns.Add( "Price", GetType(System. Int32))
DT.Columns.Add( "ID", GetType(System. Int32))
DT.Columns.Add( "Vol", GetType(System. Int32))
Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChange s()
Not really. One exception is the PK which is indexed.
Thank you
How can you create PK on the dataTable ?
"Brian Gideon" <br*********@ya hoo.comwrote in message
news:b1******** *************** ***********@b38 g2000prf.google groups.com...
On Sep 18, 8:41 am, "fniles" <fni...@pfmail. comwrote:
Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.
Dim DT As New DataTable
DT.Columns.Add( "Price", GetType(System. Int32))
DT.Columns.Add( "ID", GetType(System. Int32))
DT.Columns.Add( "Vol", GetType(System. Int32))
Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)
r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChange s()
Not really. One exception is the PK which is indexed. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
by: Oliver Drobnik |
last post by:
Hi,
I have a datagrid bound to a datatable. Now if I sort the datagrid by
clicking on one of the column heads I can no longer use the index in the
datagrid to find the corresponding row in the datagrid.
How can I find out the new (sorted) index if I know the row in the
datatable?
kind regards
|
by: Jason Callas |
last post by:
I have a process that manages a list of trades. Each trade is a separate row in the table. I blast the process with 10,000 new trades in order to stress test it and end up with the below listed exception when I call the NewRow method. The number of times it happens is NOT consistent (sometimes a few times out of 10,000 and sometimes 1000+ times). The app is written in VB and I am using SyncLock everywhere the table is accessed but I am sure it...
|
by: Ryan |
last post by:
Is there a way to get a row's DataView index from the underlying DataTable
index.
Example
DataTable (sorted by key - 1st column) DataView (sorted by second column)
Row 0 - A, 2 Row 0 - B, 1
Row 1 - B, 1 Row 1 - A, 2
Row 2 - C, 2 Row 2 - C, 2
I know the key of the row I want and can get the index of that row in the
|
by: jensen bredal |
last post by:
Hello,
I have a Datatable "dt" with say "n" rows.
I want to return a subset of "dt" starting at index "i" (i<dt.Rows.Count)
and ending at index "j" ( dt.Rows.Count >j>i).
How can this be done without unnecessary coding?
Many thanks in advance.
JB
|
by: Richard |
last post by:
Windows Forms, csharp, 20 rows in DataTable 14 shown in view after filter
applied. For any of the 14 how do I do the datarow or something else thing
to access the data in the row of the table behind the view selected on the
datagrid.
DataGrid only gives an index based on the 1-14 visible on the datagrid and I
can't seem to update anything I see in the dataview quickwatch that I can
update the underlying row. I could manually keep track...
| | |
by: JohnR |
last post by:
Sorry if this is has an obvious answer, but I can't find it...
I am using a datatable.select to obtain the rows in a datatable that meet
certain criteria. My question is this: for each of the datarows that are
returned to me as a result of the datatable.select how can I determine their
index in the datatable.rows collection?
For those interested in why, it is because the index in the datatable is the
same as the index of the same row...
|
by: =?Utf-8?B?UnlhbiBBbmRydXM=?= |
last post by:
Does the int index of the DataTable.Rows collection place a size limit on how
large a datatable can be?
If not then how do you index DataTable.Rows for sizes greater than what an
int can handle?
|
by: Ryan Liu |
last post by:
I have a program works fine in .NET 1.1 and just recompiled in .NET 2.0
without any code change. Compiles OK, but there is an exeception when
execute it.
Then I remove PK, it works all fine again.
Is this a known bug : PK on auto increase DataColumn in DataTable cause
NullReferenceException?
dcLineId = new DataColumn(LINEID_STR,
|
by: fniles |
last post by:
I am using VB.NET 2005 and Access database.
My program uses a timer that kicks in every 1 min to read from a database
and copy the dataset table to a datatable.
This database is in a class called clsStat.vb.
Then I pass this class to a thread.
Each thread will call a function inside the clsStat.vb to do a "Select" of
the datatable.
Every day around the same time this function that does the select of the
databale gets errors like so:...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
| | |
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
by: 6302768590 |
last post by:
Hai team
i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| | |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |
