I have a system whereby I have a SQLite database with around 200+ records. I basically need to cycle through all rows, get the value from one of the columns, perform an algorithm, then re-insert the value.
I know I could do this in a long engrossed way, by getting all data, updating in arrays and such, and then re-inserting via tons of sql queries, however this seems a bit slow and I am sure there is some better way of doing it.
i'm just starting with sqlite, as apparently its quicker than access for a real time logger. i'm using this as a tutorial - i didn't install the runtime support with SQLite as it causes issues when using 2008 express.[URL]..
but it seems the data isn't being written to to the db. i can't tell exactly because i dont have a program to view the table contents, only to view the setup of the db.
I'm a little confused about checking values in a database. What I want to do is see if a tuple such as the following exists:
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The invoice_num is not null, it's blank: " ". What I want is to find if such an entry exists, where the invoice_num is " " and update it with a number entered into a textbox. I'm a little confused about if statements and cases in SQL, so if someone could point me in the right direction, that would be great!
How do I updatezz data from 2 rows to 2 columns?
tool: vb.net
server: MySQL (SQLyog)
I have 2 tables, membercardlist and memberinfo:
table membercardlist:
------------- ------------ ------------
| AccountNo | CardNo | status |
------------- ------------ ------------
| 9999 | B009 | inactive |
[Code]......
I have a dataset which is bind to a datagridview. When changes are made and that dataset is modified, i want to edit the dataset and update two datarow with WHO did the change and WHEN did the change occur.
View 1 RepliesI'm trying to learn t-sql and my reading material all say to update all the rows at once instead of processing row by row. How would I go about doing that if I'm using object data source? I can see how I would do it if I'm using a dataset/datatable, but if I'm using a List(of object) as my data source for a datagridview, how would I update all the rows in one go?
For example, let's say
Business layer - I have a Person class with generic properties (name, age, gender, occupation, etc.)
Database layer - I have a method that retreive all the rows in my Person table, and return it as a List(Of person) to be used as the data source for my grid view.
I make a bunch of changes that affects multiple records, and instead of having a button on each row in my datagrid that update that specific row, I want an "Update" button that update all the records.
I'm using an access database in a program that I'm making for my school, the user is able to select an item from the menu, then it sends it to a list box, there is also a textbox to put a quantity of how much of the item you want. I have a field in my database called Amout Ordered, I want to update it with the amount of each item ordered, and I can't figure out how.
View 1 Repliesi found this code to update a property on an active directory entry:
If user.Properties.Contains("title") Then
user.Properties("title")(0) = employeeTitle.SelectedItem.Text
Else
user.Properties("title").Add(employeeTitle.SelectedItem.Text)
End If
I understand it except for the ("title)(0). why is this a double index array. what does the (0) do?
I am able to load a dataset with records from a sql database. I then loop through the data using a for loop, this works fine. As part of the loop I would like to update the contents of a textBox.text property. The problem is that it will only update the text field when the loop is complete. How can I update the text content for each record in the loop? I hope this makes since.
View 5 RepliesI know that when I add a record to a table through a binding source using a binding navigator - it completely handles the IDENTITY PK (it's bound to a textbox and you can see it immediately).
Now I'm trying to do this differently in another part of the program - here I only have a BINDING SOURCE - that's bound to a DATAGRIDVIEW.
I put a new record into the DGV like this
Private Sub vendorfilesDGV_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles vendorfilesDGV.DragDrop
If e.Data.GetDataPresent(DataFormats.FileDrop) Then
[Code]....
I have a piece of code that is suppose to update the password field when the user wants to change password but I get an error line:
An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in system.data.dll
error line: cmd.ExecuteNonQuery()
If BindingContext(ds, "login").Position < 0 Then
MsgBox("Database Is Empty !", MsgBoxStyle.Information, "Records Management System")
Exit Sub
End If
If ComboBox1.Text = "" Then
[Code] .....
I'm having some trouble getting cross-thread communication/field-updating working properly in my VB.NET 2010 program. I'm trying to update a field on my main form whenever a thread that I've started throws an event. Here's a simplified version of my code:
My main form:
Public Class Main
' stuff
' Eventually, startProcessing gets called:
[Code]....
I have a data set that I am pulling from. I have no problem pulling dats into a text field but it doesn't sidplay in a drop dowl list.The Try witha text field brings back the dat without a hitch, but the Try with a ddl bring back nothing
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I have two tables:
*Transaction Record
*Account Details
Account details table has the field "Account Number" as its primary key.
Transaction record has the field "transaction number" as its primary key and "account number" as its foreign key. This is a table created in ms access. I am creating a program in vb.net to maintain this database.
When i try to find rows using an oledb_data_adapter, an error occurs stating that there are muliple values.
i think this is due to the fact that the records in the transaction details table are being selected by the account number. Many records in the transaction details table can have the same account number.
i need a coding to help me display the most recent 10 transaction records of one account number, one after the other.
P.S: transaction record table also contains "transaction date" field.
How do I dynamically display the 'Edit' on the hyperlink field based on the values on the rows, generated from the database. the gridview automatically generates rows.
View 1 RepliesI have a datagridview and trying to filter recs based on a Date field. This is the
Dim ds As New AOListingDataSet
Dim da As New AOListingDataSetTableAdapters.CallwithNameTableAdapter
da.Fill(ds.CallwithName)
Dim dv As New DataView(ds.CallwithName)
dg1.DataSource = dv
[Code] .....
It works ok when filter is on other fields but brings empty on 'CallDate' date field. I have declared the 'CallDate' field in db as long date format in Access.
I have a simple query that fills a datatable from an Access DB. There are about 1.7 million records returned, so I would expect it to take a little time. At first, the query was a very simple one, and it took a couple seconds to fill the datatable. However, I really wanted the ability to restrict the rows by a certain date field, which meant a single INNER JOIN to a different table. Having written this, I verified that it was correct by copying the SQL string into the query builder in Access. The query, in Access, took a couple seconds to complete. That was comparable to the time I was seeing before I added in the join.
However, in VB, the query isn't completing at all. After 60 seconds, I get a message about a ContextSwitchDeadlock stating that it hadn't been able to transition or pump messages in a long time. Frankly, since the exact code works fine when I remove the JOIN, this seems like it is either a deadlock internal to the Jet engine, or the error message is an artifact of a very long running query. My question is why a query (albeit a large one) is hanging in the VB program when the exact SQL runs in a couple seconds in the Access query designer, and when I remove the JOIN, the query runs in a couple seconds in VB?
I have an access table that I'm loading into a dataset, then I'm binding the dataset to a bindingsource. The bindingsource is the datasource for a datagridview. I can use a command builder to update the entire table, but I need to update all the rows (or changed rows) in specific columns. I have a column called "dPrint" which is Boolean. I'm not sure how to use the bindingsource as my datasource in an Update Command. I've tried this:
View 8 RepliesI have an issue with a data base updating it won't update for me in debgging mode it is stopping here on this bit of code which is highlighted in red. the error which comes up is .(update requires a valid update command when passed datarow collection with modified rows.)
Public Sub UpdateDataSource(ByVal ChangedRows As database.dataset1)
Try
'The data source only needs to be updated if there are changes pending.
If (Not (ChangedRows) Is Nothing) Then
[CODE]...
I have a query that I have to run that requires me to get rows from a table based on the value of a field in another table (which I have gotten earlier). I currently have it done like this (simplified).
[Code]...
I am completly flummoxed!!! I have writen code for updating my table from a form but when I use the same code only changing the table names it wont work I get the following message: "Update requires a valid Update Command when passed DataRow collection with modified rows" My codes are as follows:
[Code]...
Here's a list example
SortedList name = test
"nothing" | 0
"something" | 1
How can I go about running a for each loop or something to add each first column in test to, say a listbox.
Listbox should just have listed.
nothing
something
I tried
For Each i In text.Values
lbTest.Items.Add(i)
Next
But that produces:
0
1
Just had a question regarding a Windows Form Application in Visual Studio 2008.I was wondering if it is possible to have a RichTextBox and have a < (previous) and >(next) button. When the user selects the Next button, a new blank RichTextBox will be displayed, when the user selects previous button, the prevoius RichTextBox w/ whatever text was in there before will be displayed.
View 2 RepliesIn Visual Studio 2005 Visual Basic, I want to create an exe (without any forms) that will cycle through each file in a folder. I have not found any method of cycling through file names in a folder.
View 1 RepliesNow what I am trying to do is to find cycles in my graph. I have a user drawn graph using lines. Now what I want is to find out if any cycles exist in the graphs. My idea is to find a way to recognize a closed shape and then fill it in. I get this idea from ms paint , where if you draw shapes, the lines must intersect each other and form a cycle for the color to be in.
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I am familiar with the VB6 ADO way of dealing with SQL queries and looping through the record set results.
However, what is the correct way to query a server, cycle through the results, and dispose of my query in VB.Net? All the ways I have been using seem to be unstable and crash randomly.
I have been using the following code:
Public Function GetSQLTable(ByVal strSQL As String) As DataTable
Dim table As New DataTable
Dim adapt As SqlDataAdapter
[Code].....
how can I step in a for cycle on the following index?
f.e.
for i = 0 to 10
if (some condition) then next i
next
I have a subroutine with a for i as integer=1 to 128 it should send 128 mouse clicks to another application sometimes it does sometimes it doesn't (it works well until it reaches 64 then the numbers go crazy). i suppose that because vb debugger reports that for my form there are 2 threads running (i have a Core2Duo processor and i've read somewhere that multithreading has something to do with the processor).Is there anything i can do to make the cycle reach the 128 clicks? i've tried setappartmentstate to STA, i've tried synclock monitor.enter nothing works, it fails it returns from the subroutine to where it started from and the next time the same story
View 8 RepliesMy application creates MDI Children programatically. I have a frmBrowser as an MDI Child which I create multiple instances of. There are several other MDI children in the MDIParent. How do I only cycle through the frmBrowser MDI children?
For Each Child As frmBrowser In frmMain.MdiChildren
'perform action on child
Next Child
The code above gives an error for all the Child that aren't of the type frmBrowser.
i need to count the number of iterations which occure in algorithms Blowfish, DES, and RC4.
blowfish i use this class DES i use DESCryptoServiceProvider and for RC4 i use this class Public Shared Function RC4(ByVal bytes() As Byte, ByVal key() As Byte) As Byte()
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