"select Count()" Is Very Slow?
Jul 19, 2010
I have a database with 1,000,000 records and a query like this:
select count(code) from table1
It works well on the local system but becomes very slow on the network. Other queries like select * from table execute quickly, but select count(code) from table1 is very slow. I can't change the database's structure. My database is Foxpro and I use VB.NET.
Edit: Should I write code like this?
dim ds as new dataset
dim da as new datadapter("select count(*) from table ", connection)
da.fill(ds,"tbl1")
Then how can I get select count(code) from table1 from the dataset? Or do I have to use LINQ?
Edit 2: I mean the comparison between select count(*) and select count(code).
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Feb 26, 2010
I am trying to make a simple form that will display a count when the users clicks a button. I want the count to be readable as the program loops the math. So as it adds 1 + 1, 1 + 2, 1 + 3, ect... I want each loop to display in the label. Below is the basic code I came up with, but I can not figure out how put a delay of something like 100 milliseconds in the loop. The idea is for the slower version of the basic count console app you learn in school and I basically need to slowdown the math and display the sum as the loop loops.
Below is my code.
Private Sub xButton_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles xButton.Click
Dim xCount As Decimal ' Count
Dim xSum As Decimal ' Sum of loop
Do Until xSum >= 100 ' Limit the count
xCount += 1 ' Count by 1
xSum = xCount ' Sum = Count
xReadingLabel.Text = xSum ' Display Sum in Label
Loop
End Sub
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Feb 15, 2011
I have a directory searcher that is looking for dynamic groups.When I try to process the results it is taking 30 seconds to return the results.the ds.findall is very fast but when I try to find out the number of records returned or anything about the results it take the 30 seconds. So i am assuming that this is where the actual retreival of information is taking place.[code]
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May 25, 2011
I'm developing a piece of a system that basically migrates data from one set of tables to another set. Everything works fine, but I've decided to employ transactions instead of just failing on things that are partially completed. (That is, if some exception occurs, I want to rollback instead of having partial data migrated.)
I have a service (in the 3-tier architecture way, not web) which begins a transaction on the data access layer. The data context is shared in the data access class which contains many methods. Those methods use various LINQ-to-SQL techniques to update/insert/delete. All the LINQ-to-SQL "selects" are within CompiledQueries. [code]...
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Jul 16, 2010
I'm trying to get a simple count of rows meeting some criteria. The value returned does not coincide with the correct number of rows when running the same query in Management Studio (SQL 2005)
vb.net
Public Function RowsAffectedCount() As Integer
Dim result As Integer = 0
[code]....
'result' always returns 1, but I have 3 records meeting that criteria in the database. Been staring at the code for a couple hours now and can't figure it out... I just need to know if the Count of rows returned from a SELECT statement is greater than 1 (at least two records).
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Jan 12, 2012
I want to do a SQL SELECT COUNT in VB .NET to an Access DB. I can get the code to work using a text fields and text criteria but if I use a date field and Date criteria it returns 0 when there are some 47 records that it should count.
Dim Results As String
Dim InvDT As String = Date.Today
InvDT = "#" & InvDT & "#"
Dim strCnn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=S:MainData.mdb" connection string to your DB'
[Code] .....
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Feb 24, 2009
how do i add a count down (eg, 20secs) and unless the user clicks something, then "Yes" is automatically selected? [code]
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May 25, 2011
My tables sectionName column has an existing value. I want to update its Adviser column but my select count always evaluate to false. I want to check if my table's SectionName column record matches the selected value of my CboSectionName. if there is a match then i'll check if such section has an adviser already. If there is an adviser already, then ask the user if he/she wants to change the adviser of that section. If he/she wants to change/update the adviser then update it else exit. however, if there is no adviser yet then assign an adviser to column adviser from cboAdviser. If no record yet in table's SectionName column then prompt the user that there is no section name yet, then exit. I have been debugging the code below for hours now but I can seem to locate why my sql count always resulted to false. [Code]
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Aug 21, 2010
I've tried to write a code which will count the orders for each person in my users table. This is what I have but it's not working. What is wrong?
vb.net
Dim command As New SqlClient.SqlCommand("SELECT *, COUNT(Orders.Username) FROM Users LEFT OUTER JOIN Orders ON Users.Username = Orders.IssuedBy ORDER BY Users.PersonName")
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Apr 21, 2009
I'm trying to access the Count Property on the array of rows returned by the datatables select method, this is after converting the Web Project to 3.5
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Nov 2, 2010
I have added a column to a Datatable called CallsPerDay which is there to tell me how many telephone calls have been made on a particular day or days.Is there a datacolumn.expression which will allow me to Filter on the day, count the rows and then populate this added column with the result.
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Jul 16, 2010
I have some reports that I use with the MS ReportViewer and I need to get a count of the physical pages (as opposed to logical page count) to use with a print dialog. I've implemented a workaround so the ReportViewer control displays the correct number of physical pages, but is there a way to get that value from the ReportViewer control? The only publicly accessible property gives the logical page count.
[Code]...
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Feb 18, 2011
Basically, Is it possible to get a grids row count using jquery.if my grid has 20 rows in it not including the header or footer, i want to now the count of actual rows, this will tell my users how many tasks they have in their list.
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Dec 10, 2010
designing a Windows based computer program that will allow a user to enter some number (n) and a choice of a count up or count down for that many numbers. So for example, the user enters 5 as their number and selects the count down option, the message box displayed would contain the message: "Here are your numbers: 5,4,3,2,1,0"
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Oct 1, 2011
This is what I have, but It doesn't work with strings for some reason (only text files):
[Code]...
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Jul 5, 2009
I am looking for a way to count words in VB My full code is as follows Public Class lblTranslator
[Code]...
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Oct 6, 2010
Declare some class level variables that will keep track of the sums for each column. For example:
[Code]....
During the RowDataBound event, retrieve the data from each column and add it to the appropriate sum. I'm not sure if you are developing an ASP.NET application or a Win-forms desktop application so I cannot help you any further at this point. What have you tried so far to solve the problem?
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Mar 31, 2009
this its a very silly problem i have with CheckBoxList control, i dont know if its just me or what but the whole idea of the control its just great but the implementation its very confusing.
im trying to eval something like this
if CheckBoxList.Items.Item(CheckBoxList.Items.Count-1).Checked=true then.....
or something like
CheckBoxList.CheckedItems.Item(CheckBoxList.Items.Count-1) = Checked then...
the problem its that i dont know how does the checkboxlist works but it just sucks that they had to make it so confuising....
i've handled lots and lots of collection controls and they all work in a similar and simple
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Oct 8, 2009
I have a fair bit of experience with VB.NET and C# (In this case I chose VB.NET, blame my laziness), but I do most of my professional work using PHP. I have no experience what so ever in using any database with VB.NET let alone MySQL.Just FYI, at the moment I am only trying to Query the database to gather the information required to activate. The Activation wizard and algorithm building (which is finished anyway), and everything else will come soon. I chose the MySQL database because I have experience with it, and it seems the best option for remote usage.The whole idea already works in PHP, I'm just have major issues moving it accross into VB.NET (Using the MySQL Connector.NET);I understand the basics, and all I need to know how to do is Count Rows and gain access to the other information in a row based on provoided information (in PHP, through mysql_ result)
So, here goes nothing, this is the Query code I am using in PHP to complete the job I want to do in VB.NET. [code] As you can see, I basically need to get the PHP code into VB.NET to fit into the 'btnQueryDB.Click' Command in VB.NET. By Equivalent, the Product ID in VB.NET will come from 'txtPID' and similar, Serial Number will come from txtSNUM. Once counted to be 1, the Activation Code and Status will be fed into 2 other text boxes in the form. (acCode, and acStatus).
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Jan 27, 2011
IT STILL GIVES A MSGBOX IF I SELECT THE CHECKBOX BOX OR NOT ....My code below will redirect to Google in both conditions: If the user selects the checkbox, then it will redirect to www.google.com, but if a user forgets to check the checkbox then it shows the msg box with an ok button. When I click on ok it should redirect to www.google.com
I want When a user forgets to check any of the checkboxes to show a msgbox with an ok button and stay on the same page. Otherwise if user selects any of the checkboxes then redirect to google
[code]...
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Mar 29, 2011
i am trying to auto select the email value from a 2nd cbobox when the user selects a name from the first cbobox using the first cbobox's index. (the values all line up with each other just fine)This is my current code:
Private Sub cmbAnalyst_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbAnalyst.SelectedIndexChanged
theAName = cmbAnalyst.Text
[code].....
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Oct 3, 2011
I have two drop down. SelCurrentManuf and selCurrentModel. I want the option in selCurrentModel to change depending on the option selected in selCurrentManuf. How do i do it?
<asp:DropDownList runat="server" ID="selCurrentManuf"></asp:DropDownList>
<asp:DropDownList runat="server" ID="selCurrentModel"></asp:DropDownList>
This is how i am currently populating selCurrentModel
Public Sub PopulateCurrentModel()
Dim mySelectQuery As String = "SELECT * FROM Model where ManufID = "+ selCurrentManuf.Text+";"
Dim myConnection As New MySqlConnection(Session("localConn"))
[Code]...
but it only populates the first selected manuf, and doesnt change after
Private Sub selCurrentManuf_SelectedIndexChanged(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles selCurrentManuf.SelectedIndexChanged
PopulateCurrentModel()
End Sub
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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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Sep 16, 2010
I need to set a select back to it's default value after it's been changed based on certain conditions.
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May 13, 2012
am developing a project and i am trying to use this code with my table which is under microsoft access 2010
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Feb 1, 2011
I make a program to check certain website.
The idea is to do webclient.DownloadStringAsync thingy and then wait till each one is solved. So like multi threading application.
The program itself is a single thread.
Well, when I loop 400 times it takes too long. Every time I press pause the program in debug it stop at this line[code]...
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Oct 21, 2011
Currently, the sendkeys command is too fast for a game called "Minecraft" to process. Here is the code I got currently:
for the button:
appactive("Minecraft")
timer1.enabled
[code].....
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Oct 13, 2009
Something happened to my VS2005 setup and now the first time load for F1 can take a full minute to load. I think the last significant thing I did was install an add-in for ESRI ArcExplorer. I uninstalled that add-in but help is stil VERY slow to start.Does anyone recognize the problem and have a simple fix?
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Jun 9, 2011
Is there any way that i can be able to get the ExecutenonQuery to Execute faster. Am using it to run mysql queries that have joins from diffrent tables. As I have come to notice, the user has to wait a while before the statement ExecutenonQuery can be completely executed.. is there any way that I can get it to execute faster?
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Sep 3, 2011
Im using VB2010 professional edition and Ms Access 2007 DB. Main form contains a button which accesses database, fetch results in textboxes and update database. But sometimes it takes almost 40seconds to fetch and sometimes it fetches immediately. Couldn't understand any pattern for this. The table in the database contains 8000records and Main form has 3000 lines of code.
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