.net - How To Select Data From Datatable
Feb 23, 2012
I am little bit stuck here .. I have a datatable as _
Dim dtPupil As New DataTable
dtPupil.Columns.Add("PupilId", GetType(Integer))
dtPupil.Columns.Add("Forename", GetType(String))
dtPupil.Columns.Add("Surname", GetType(String))
I made a select (assuming names combination will be unique)
Dim strQuery As String = "Forename ='" & forename & "' and Surname = '" & surname & "'"
Dim dr As DataRow()
dr = dTablePupil.Select(strQuery)
I wanna have PupilId as an Integer of the row that match, so
Dim PupilID As Integer = ??????????
What do I need to write here ? There will only be 1 row returned.
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Dec 19, 2009
The next step is I need to build a randomizer to randomly select a row and read the columns of that row into varibles.I have a working randomizer that can randomly pick a number between min and max values but what I don't know if how to select a row / How to find out how many rows are available and how to read the values into varibles.Am I right in declaring an Integer Varible then using:
AvailableRows = DDT.Rows.Count
Then use my Random Function to pick a number between 0 and AvailableRows
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Sep 28, 2009
I have a search function on my company's website (based on .NET 2.0) that allows you to narrow the product catalog using up to 9 different fields. Right now, after you make your selections on the frontend I am building a dynamic query and hitting the database (SQL Server) to get the resulting list of items numbers. I would like to move away from hitting the database everytime and do all of this in memory for faster results. Basically a 3500 - 4500 row "table" with 10 columns: the item number (which could be a primary key) and the 9 attribute fields (which have repeating values for many many rows).
There can be any number of different searches between the 9 columns to get the items you want:
Column A = 'foo' AND Column D = 'bar'
Column B = 'foo' AND Column C = 'bar' AND Column I = 'me'
Column H = 'foo'
etc...
Based on my research, the .Select() function seems like the slowest way to perform the search, but it stands out to me as being the quickest and easiest way to perform the narrowing searches to get the list of item numbers:
MyDataSet.Select("Column B = 'foo' AND Column E = 'bar' AND Column I = 'me'")
In my specific case, what method I use as an alternative that has the same narrowing functionality and better performance instead of settling for the datatable.select() method?
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Aug 18, 2011
I am trying to display value of the field ("UserID") for every row exists in datatable to checkboxlist(make the checkboxlist item selected).
I used for loop, but only the field value from last row of RoleUsers table is selected in the checkboxlist.
Here is my code
Private Sub DisplayRoleUser()
Dim conn As SqlConnection
Dim cmd As SqlCommand
[Code].....
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Apr 8, 2009
I am getting array of selected datarows from a datatable.select.I use the commands below to get that array or datarows
Dim foundRows() As DataRow
strExpression =
Here is what I tried.I have looked at examples by MS but they all just write to the screen and I have no interest in that.
For Each rowWork In foundRows
dtWork.Rows.Add(rowWork)
Next[code]....
"LineOfBusiness = 'CPP'"
foundRows = modXchange.pdtWork.Select(strExpression)
Now, I want to place the rows from foundrows into an empty data table.I did what I thought was the obvious but that only returns a bunch of rows with no data
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Aug 2, 2011
Unable to select multiple column in datatable
Code:
Dim Activitydtb As DataTable = DirectCast(ViewState("TalentcharacterActivty"), DataTable)
grdviewactivity.DataSource = Activitydtb.Select("SELECT
[Code].....
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Apr 4, 2011
I have a select statement and it will go to a datatable object, I would like to do the following
textbox1.text=datatable(first field value)
textbox2.text=datatable(second field value)
textbox3.text=datatable(third field value)
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Dec 15, 2009
I thought this would be simple but obviously not!
Basically, I have a date and want to do a 'between' on two date columns like this:
myDataTable.Select(myDate & " between (StartDate and EndDate)")
Where StartDate and EndDate are date columns that do exist in the DataTable.
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Apr 9, 2012
I have a datatable and I would like to get the MAX number from this table where Term Number (first Column) is a certain value. If my datatable is declared as dtMyTable, I'm assuming I need to use dtMyTable.Select(), but I'm not sure if this is the best way.
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Feb 24, 2012
I'm trying to get value from Datatable after Select Method.Select Method should return only one record.
Dim y As DataTable = CType(HttpContext.Current.Session("tb"), DataTable)
Dim products = y.[Select]("StnID" = "'" + stnID + "'")
Dim size = DirectCast(Products(0)("Shape"), String)
if I replace products with y--(DirectCast(y.Rows(0)("Shape"), String), it works.(which is before Select method, so it's useless) products is datarow object and I can't seem to get the value same way as datatable.How do I get value from datarows?
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Nov 20, 2011
I have pulled information from a database into a datatable (dtCustomerInfo) then I expanded on the columns by processing the data and I can display this in a datagridview without any problem. However, the data is in detail and I want to ultimately summarize by customer name.The code below has a commented sql statement that is the statement I ultimately want but it is not working. However, the idea is that I want to Select from one datatable into another but run aggregate sum on several columns so that I will get one record per customer showing totals for each column.So I broke it down to just pull all data possible into the second table.[code]I do know the grouping in the current select * statement does nothing but my issue is more that the columns do not show up.
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Jun 6, 2010
I need to Quarry from Data Table Like
select Name, Address from myDataTable where name = 'x'
and
select distinct(name) from myDataTable
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Dec 28, 2010
I need filter for multiple values on one column using the DataTable.Select method.
Dim totalFatal As Integer =
m_DataSet.Tables("tblAccidentNonMotorist").Select(String.Format("[AccidentNumber] = '{0}' AND CONTAINS([InjuryClass], '"01" OR "02" OR "03"'", accidentNumber)).Length
[code].....
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Apr 8, 2009
I was trying to write the following select stmt but i am getting an error that the parsename is not identified.
[Code]...
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Oct 31, 2010
how to copy data from datatable to table in dataset i ry this but its readonly property
ds.datatable1=newdt.copy
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Aug 10, 2011
I am updating a data table (dt_report_crypt) from an encrypted csv file in the code below:I decrypt the colums and update the same dreport_crypt, such that it will contain de-crypted data.This part is working wellI however need to use this de-crypted datatable as a data source to update a second table(dt_report), using the sql SELECT command to filter relevant data,
Dim dt_report As DataTable
Dim dt_report_crypt As DataTable
Using cn As
[code].....
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May 15, 2012
I m' trying to select a row and then edit, and no error on debuggiing but the changes are not saved on the database
[Code]....
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Mar 20, 2009
I understand that DataTable.Select() returns an array of rows. I just want to know whether these is a way to get the row indexes as well.
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Aug 12, 2009
I've defined a function:
Public Class GeneralFunctions
Function StartsWith(ByVal sStart As String, ByVal sWord As String) As Boolean
Return Strings.Left(sWord, Len(sStart)).Equals(sStart)
[code].....
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Jun 11, 2010
I am working on a vb.net app for a handheld using Windows CE and I have a few columns of data loaded in a datatable from a text data file. Some of the records can have duplicate Account IDs so I cannot use a primary key. What I want to do is take an Account ID entered and filter on just those records. I need to loop through all records with this Account ID, make updates to any of them and then clear the filter.
how to set a filter on a column based on a given string such as an account number? And loop through these records? Can I modify the records at that time?
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Feb 19, 2012
Is there a function to write this in DataTable Select method in VB.net?SQL Query that I would like useSELECT id from mytable where id in ('a','b','c')
I have this code to create query but it would be nice if I can use IN clause
For Each typeitem In shapecb.Items
If Stntypeitem.Selected = True Then
[code].....
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Mar 28, 2010
I want to filter a virtual table (DataTable) and return only matching items into another datatable which eventualy is the datasource of a datagrid. The datagrid displays the result. The purpose is to reduce the network traffic while still providing the function. So as type on the textbox provided, the virtual table which was earlier populated by a disconnected Ado ADO connection, is re-queried and filtered into the new datatable.
how to go about this. It is a windows application and i am using dot net 3.5, VB 2008.
Here is my code:
Dim filtDT
If MYQDT.Rows.Count <= 0 Then
MsgBox("The data is been cleared")
[Code]....
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Jun 15, 2010
I am trying to use the Select on a datatable and am having some trouble. I got it to find a match on rows in a datatable I fill with data in multiple columns. But I cannot seem to loop through the results to do something with it. Here is my code below. The table is already filled with data.
[Code]...
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May 14, 2011
I have a dataset, which have a column create_date which have value(5/12/2011 12.54.00) , but i want to select the value from dataset with date only not by time (i.e. 5/12/2011),[code]
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Mar 17, 2012
I have the following code that loads an XML file into a datatable (I went this route because I do not know how to query XML directly). I want to use the Select method to return a row where "age = 72". However, I can't seem to get this to work. Also, if there is a better way to search through a datatable for specifc values that would not require iterating through the whole table to get the results
Imports System.Xml
Module Module1
Sub Main()
[Code]....
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Nov 5, 2008
i have a datatable that contains numerous postcodes in the following format[code].....
there is always a space before the last 3 characters now i need to filter the datatable against a list of excluded postcode areas..these are the following format:-
BT1
BT2
BT4
BT40
so its either 2 letters & 1 number or 2 letters & 2 numbers, no 2nd part to the post code..i have a little function which builds the string, and then removes the rows from the dataset like so (ive pasted in an example postcode string)....[code]....
which obviously brings out no records as they all have full postcodes the issue is, i need to be comparing only the first half of postcode BTxx bit but cannot use a % wildcard, as this then would bring out BT40's when i only want, in this example, BT2 & BT4's..so is there a way to make it compare against the first half of the postcode?
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Sep 9, 2011
How do i use Datatable.select method to select only those rows where a specific column value is blank?
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Mar 7, 2012
The following VB line, where _DSversionInfo is a DataSet, returns no rows:
_DSversionInfo.Tables("VersionInfo").Select("FileID=88")
But inspection shows that the table contains rows with FileID's of 92, 93, 94, 90, 88, 89, 215, 216. The table columns are all of type string.
Further investigation showed that using the ID of 88, 215 and 216 will only return rows if the number is quoted.
i.e. _DSversionInfo.Tables("VersionInfo").Select("FileID='88'")
All other rows work regardless of whether the number is quoted or not. I understand that the numbers should be quoted just not why some work and others don't?
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Dec 20, 2011
im having a problem with the Select() method in my datatable. If i want to search in my DataTable for multiple patterns (search function) For string Columns the 'Like' works
[Code]....
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Aug 15, 2011
I was wondering how i could pass the following SLQ function to my datatable:
Select sum(Quantity) from Purchases where transaction_mode=1
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