I am connecting to a MS-Access 2007 database using VB 2010 and OLEDB. Conducting the following test seems to suggest that MS-Access does not interpret DBNull.Value correctly when sent as a parameter from OLEDB:[code]
View 2 RepliesFor some reason every time I execute the code, it gives me the error "No value given for one or more required parameters" and it points to the ExecuteNonQuery. Below is the relevant code I have.
Public Function sqlUpdate(ByVal varBalance As Double, ByVal varWithdrawlAmount As Double) As Double Dim dbCon As New OleDb.OleDbConnection dbCon.ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = dbATM.mdb" Dim query As String Dim cmdUpdate As New OleDb.OleDbCommand dbCon.Open() varBalance = varBalance -
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in pervious version of VB (DAO 3.6) I used to be able to delete a query object and then creating it again (not the records) using the code below. but I am having a hard time finding how to do it using the OleDb in VB.net.
Dim ws As Workspace, db As Database
Dim qy As QueryDef
db.QueryDefs.Delete ("WISE QUERY")
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I have a program (below) which runs an SQL query on an Access database to bring back records based on the date a user selects. This issue seems to be that US date formats are the only date formats that SQL queries accept. I may be wrong, but this is my understanding. All my dates in the database are in EU date format (dd/mm/yyyy). What happens when i run my code is that I can not access a record with the date of 08/05/2010 unless the input date is 05/08/2010.
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Why does the following code: A = not IsDBNull(CurRow("BuyBook")) AndAlso CType(CurRow("BuyBook"), string) = "Yes" results in the following error:
Conversion from type 'DBNull' to type 'String' is not valid.
I've created a small WPF app in VB9 to catalog our sizable DVD collection. This exercise has been more about learn programming than the need to have a movie database app, but I digress.The SQL database I created has a field for "Genre" that does not have an entry for all the movies in our collection. As such, when I run the method that filters the movie listing by "Genre" the compiler throws the "StrongTypingException was unhandled" error stating "The value for column 'Genre' in table 'Movies' is DBNull.".
I now understand where the DBNull problem comes from and have been searching for several hours to find a VB solution that converts the DBNull fields to strings on the fly during the LINQ query. I've found many solutions people have tried but, since I'm quite new to all this, none of them have worked for me. Pasted below is the method that throws the exception.
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I have the following code:
' Now retabulate the current occupancy.
For Each row In assignments
Try
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I'm trying to connect and query a .dbf dBase table. I'm fairly certain I've got the connection string formatted properly, because I am no longer receiving errors that I can't locate the table.I've tried everything I can think of, and nothing seems to work to make a valid query. I've tried all sorts of syntax changes around the table name (which is just 'buildings'...nothing fancy). The error is a syntax error with an incomplete query on the executereader line.
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I have the following code which will only return one column of 41.
vb.net
Using Command As New OleDb.OleDbCommand("SELECT * FROM Products_TAU WHERE ItemID= @ItemID", Connection)
Command.Parameters.AddWithValue("@ItemID", ItemID)
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That table alone is filled with 76 records and has 41 columns of data to pull.. this is only returning the first column of the row indicated by the where clause.
Before I had the where clause call it by lineID which there is 4 records of that... and it was able to pull 4 columns from it...
I have a linq query which loads approx. 1000 lines into a variable, during that process I want to display a progressbar, not necessarily stating the percentage, can be marquee style, doesnt matter.
This progressbar is on a modal form to precent the user from interacting with the app for the time the query's running.
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I'm a new member to this site, and I have been searching for a solution to this problem.. Although I have found variations in the problem, nothing has seemed to work for me. Just started programming last year.
I am trying to populate text boxes in a form based on information from an Access Database. Everything is working, except when there are empty field values; the program then crashes because a DBNull value is returned. I set up an if statement to check the index as the rows are read for DBNull values, the problem is How do I actually change the value in the field from DBNull to a blank string ("") ?? Everything I try gives me an error, most often saying something about setting up an object. The problem happens within my if statement of the do loop...I'm thinking maybe I need to set up parameters ? Or an actual edit session within a datarow variable?[code]...
You can query active directory with an OLEDB provider called ADSDSOOBJECT. This works great except it only returns the first 1000 rows. The following article shows how to work around this limitation in a vb script by setting the "page size" property of the command object. [URL]..I have been able to reproduce that code in VB.NET, but I am having problems getting it translated to OLEDB syntax, because there doesn't seem to be a "Page Size" property, or indeed a "properties" collection of any kind, in OLEDB.
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I have database with table called "Konzultacije" with field "Vrijeme" (Date/Time). I have datagridview (DGKonzultacije) with columns. Column (1) data format is set to date/time. I want to delete record from "Konzultacije" table depending on selected cell in datagridview but only I can get is error.
This is my code:
Dim iSql As String = "DELETE FROM Konzultacije WHERE Vrijeme = " & DGKonzultacije.CurrentRow.Cells(1).Value
conn.Open()
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If i add apostrophe like this:
Dim iSql As String = "DELETE FROM Konzultacije WHERE Vrijeme = '" & DGKonzultacije.CurrentRow.Cells(1).Value & "'"
error is raised: Data type mismatch in criteria expression.
I am trying to interpret a xml response that gets fed into my RichTextBox so that i can alert the user of their success when posting a record to a website I am managing to count the number of successful and failed postings by searching for text shown below:
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I have an array of Bytes. Most of these are interpreted as Unsigned. On certain occasions I need to interprete the byte as signed. Why can't Byte convert to SByte? What I'm doing: I'm trying to program a disassembler for an 8-bit video game ROM. My program reads the ROM and processes each instruction. The instructions are interpreted as unsigned. Some arguments for instructions would be treated by two's complement in the original hardware, however, to make a signed number.
View 8 RepliesI have recently developed a small program which SQL's a MS Access database on a shared folder. I published it to the network folder and many users have installed it fine, but I have had two users who have reported the following error:Could not load file or assembly 'System. EnterpriseServices. Wrapper.dll' or one of its dependencies. The device is not ready. (Exception from HRESULT: 0x80070015)So I went to google and searched on how to get rid of this error and it seems that there are alot of sites to suggest re-installing the .Net 2.0 framework. So i tried to click repair the installation but then hit on another problem:Error 25015. failed to install assembly. 'C:WINDOWSMicrosoft.NetFrameworkSystem.EnterpriseServices.dll because of system error: The device is not ready..So i did more googling and found that it might be due to a HaxDoor virus: url...I am now scanning the system now, but it hasn't picked up any virus yet.What should i do? Is it becuase I am using oledb adapter to access MS access?
View 2 RepliesI'm successfully receiving bytes from an USB device using a HID USB .net library.Here is a sample of my code :
Dim ptr As IntPtr = USB.USB_Read()
Dim buff As Byte() = New Byte(USB.USB_ReadLength() - 1) {}
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My question is : how can I know wich button is pressed ? Meaning : I just want my program to store the button pressed and do an action when pressed.
I have an Access table ("Titles") which is connected to VB.Net using OleDb. The connection variable is conTitles.Some of the column in the table are 'No' and 'Status'.
In the Form, I have a textbox (txtTitleNo) and a button (BtnReserve).I want to put a number in the textbox, and then when I click the button, I want the 'Status' column with the corresponding number to be changed to 'Reserved'.
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I am connecting to an Access database and using a parameter query with the LIKE operator to return all rows that match query. The string to search for is taken from a Textbox
sql =
"Select * FROM Allview WHERE Info Like" &
"*" &
CStr(TextBox1.Text) &
"*"
The query does not return any data in vb, but when run from access with same string, there is data returned.The connection to the database is done correctly, as I am able to return data with various other queries.
Partial code :
Dim
con As
New OleDb.OleDbConnection[code]....
I am using the following code and a remote server:
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The problem is that the acceess rights are not recognized correctly. If I log in manually with the same credentials then the rights are set correctly. Is there something else that need to be set for this towork correctly? I just realized I clicked VS.net instead of VB.net (moderator move this to correct area.)
I am trying to run a query an Access db from VB. The general query which I want to run is
SELECT * FROM Patient WHERE Patient.PatientID = ?
or SELECT * FROM Patient WHERE Patient.PatientLname = ?
I tried using an input box which captured the user input and pass that variable to the query, but that failed. Then I read about writing a function and using that, however, I keep getting an error which says Function not defined, but when stepping through the code, it seems to work. Here is my function: [Code]
do you Create Database in MS Access Using Oledb in vb.net?
View 4 RepliesIs it possible to drop an MS Access Database using Oledb in VB.Net?
View 2 Repliesi am developing a project on "sigmoid investment solution" where i have a form where i have to enter all the recent BUY/SELL of shares. and after inserting each record i need a BUY AVG and a SELL AVG. i am using oledb connection to connect to a access database. i want to use the following sql command SELECT AVG(Price_field) FROM table_name WHERE buy_sell="BUY"..i want this result to display on a text box in the form. What is the code to connect to data base executing the query and displaying the result in a textbox.
View 1 RepliesI wonder is there another way to connect,edit access database with out using OLEDB command.I want to insert,delete data from access table without using oledb.
View 3 RepliesEditting and Updating Access with OleDb commands. VB9
View 14 RepliesI am creating some basic software for our manufacturing department. I am using Visual Studio 2008 using Visual Basic.The software has a user log in. There is a form in which the choose the worker name, the item they were making, how many were made, damaged, or received damaged from the supplierHowever when they click on the "Update" button to insert the record..i get my custom message that it failed and the record is not inserted. I put a TRY...Catch... around the insert query and it didn't generate an error message.I have been following the code in the OLEDB BASICS tutorial so I am not sure what the problem is at this time.
<add name="MFCTData"
connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\Data.mdb;Persist Security Info=True"
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I do not have a lot of experience in vb.net, but I am trying to use OleDB to insert a record with String,string,Yes/no(studentname, number, gender). However when I insert it , there's a exception raised stating that I have invalid syntax for the "insert into" query. I could not spot the error.
Test case:
txtName.Text = "asdasdasd"
txtPhone.Text = "123456789"
rGender.Checked = True
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I have been scouring these forums and the internet in general as well as doing a lot of reading, all to no avail. I can not seem to successfully update the Access database from an edited DataGridView. I am trying to use Stored Procedures that are in the Access database and work fine therein. The DGV is filled in properly. I have tried an ever-increasing number of variants to update the database (Private Sub BtnUpdate...) without success. [cod]e....
View 6 RepliesI've just picked up a project from someone who has recently left our company, and the project file for the project has somehow had XML documentation deactivated. Typing ''' no longer automatically creates XML documentation segments, and existing XML documentation within the code does not show up in Intellisense, and is also not correctly highlighted as XML documentation.
In addition, the Intellisense for the My. namespace contains only MySettings, Resources and Setting under the "All" tab. Everything else is missing. Attempting to manually write My. namespace code results in compile errors. These are not problems with the IDE; I can start a new project and both Intellisense and My. work fine in these new projects. I can only assume that this is something which has been set on the project itself.