Checking For A Duplicate On Table Before Inserting The Field?
Dec 22, 2009
I need to check if a Commodity entered into (TextBox1.Text) already exists on my table before i insert it. I'm having issues checking if the number of rows returned from my Select is equal 0? Also i'm wondering should i be checking for an exception and open/closing my connections each time i make a call to my DB or is the way i have it coded below OK?
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Try
myConnection = New SqlConnection("server=localSQLEXPRESS;uid=sa;password=12345;database=My DB")
myConnection.Open()
For some reason my code is executing the INSERT query twice and putting duplicate records in my table. If I put a primary key on one of the fields I get a runtime error and it complains about the fact it can't add the record twice.The part of the code that INSERTs is near the bottom, bolded and italicized. I put the entire IF statement of code incase my logic is wrong.This is what's being executed when a user clicks a button
If listOfCompanies.Contains(cbx_Company.Text) Then 'If the list contains the company, UPDATE the record If LaborChecked Then
I am using the DataSet to test for data errors on a DataGridView (to give the user feedback before they save changes back to the database). RowChanging event has the code at the bottom and this manages error messages on the DGV via an ErrorProvider. I want to add something to this code that esnures there are no duplicate rows (it's a 2 column table and one of those is the autoincrement PK). However I cannot work out how to do this and since the column in the database is set to Indexed (No Duplicates) it will throw an Ole error if I don't handle it, I could manage it in a Try block around TableAdapter.Adapter.Update but would prefer not to add needless round trips to the DB when it really ought to be simple to do it in the code (and preferably in the DataSet, not the form).
I found the following code (Forum Post) and try as I might I can't make it work since I can't get access to a DataTable within the RowChanging event that allows me to run DataTable.Rows.Find().
Dim expression as String Dim matchingRow as DataRow matchingRow = Mytable.Rows.Find(expression)
In my case:Mytable would be some kind of reference to the table / dataset etc.
'expression' would be e.Row.compclass.ToString
* a reference to the database table the form works with (bearing in mind that this code is in the DataSet not in the form). I've tried properties/methods of the DataSet itself; creating a new DataTable and linking it to the DataSet Table (or DB Table); creating a new DataTable and loading it with the table contents - Searching MSDN and the forums hasn't popped anything up yet.I'm currently experimenting around this code:
Dim strCompClass As String = e.Row.compclass.ToString strCompClass.Trim() Dim foundRow As DataRow = ???.Rows.Find(strCompClass)
[code]....
This is the current code in the RowChanging event. The new code would be inserted after the last End If in the code below.
Private Sub ref_compclassDataTable_ref_compclassRowChanging(ByVal sender As System.Object, ByVal e As ref_compclassRowChangeEvent) Handles Me.ref_compclassRowChanging If e.Row.HasErrors Then
I've read through all the search results for this and haven't quite got it yet. I often get given Excel spreadsheets of file names and have to check through them for duplicate names.I am making an app to do this for me. I've extracted the data from Excel I'm just having issues with checking for the duplicate. I've tried 2 different ways I found online and neither are working for me,
I have this line of codes here to check if the records exist.
Try If StudentInfoBindingSource.Find("StudentNumber", StudentNumberTextBox.Text) = -1 Then ToolStripLabel4.Visible = True
[Code].....
This codes works perfectly but there is a problem, if I close that certain form and reopen it and try to input the same student number, the ex.Message for the Try appears and still the progressbar() command executes although the data will not be saved. I want to ged rid of the execution of progressbar() how can I make it work? And as much as possible I want the message box in Else to be executed and not the msgbox in try catch.
For some reason my code is executing the INSERT query twice and putting duplicate records in my table. If I put a primary key on one of the fields I get a runtime error and it complains about the fact it can't add the record twice.
The part of the code that INSERTs is near the bottom, bolded and italicized. I put the entire IF statement of code incase my logic is wrong.
This is what's being executed when a user clicks a button
If listOfCompanies.Contains(cbx_Company.Text) Then 'If the list contains the company, UPDATE the record If LaborChecked Then
I am being forced to us Option Strict in my class and this is a new feature to me. Right now my code is having trouble comparing the current time to be added (A Date) with the list of times (Object). Here is my complete code
Option Strict On Public Class schedulebookForm ' handles Add button user event Private Sub addButton_Click(ByVal sender As System.Object, _
[Code]....
Problem is inside TimeTaken Function, inside the For.. Until. Basically the If... Then Statement. I tried. .contains, Select Case, and a few other alternatives.
I have a form where two fields on the first page of the form make up the primary key. I want to check for duplicate values before attempting to insert the record, since I don't want the user to go all the way through the form only to find out they can't submit it. So I'm trying to check for duplicate values when the user tries to go to the next page of the form. I wasn't quite sure how to do it, and sure enough I'm getting an error. ("Object reference not set to an instance of an object.") The problem is apparently in my if statement, "If myValue.Length > 0 Then", but I'm not sure what needs to be in place of that.
Protected Sub CustomValidator1_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CustomValidator1.ServerValidate 'get values
I'm trying to add a string to a listbox if there is none exact string existed inside, but it turns out a very weird error. Look at this. On form_load, I have this: AddHandler Server1.OnUserLoggedIn, AddressOf HandleUser
And then, Public Sub HandleUser(ByVal username As String) 'Here, you handle adding the text to a text box. Me.Invoke(New PrintMessageDelegate(AddressOf AddUser), username) End Sub [Code] .....
The output is when I connect the first client, it works fine. But, when I try to connect the second client, it prints out three times both the listbox1 item and the txtDisplay. It's like get caught in loop, but I have tried other kind of loops like for each and other string comparison too, still work that way.
How would one go about checking a listbox's items for duplicates? Basically I need to write a program that displays the teams from a text file provided by my instructor, in alphabetical order. I can do that, but what I can't figure out is how to prevent the For loop from adding a duplicate team. What I'm envisioning is:
If teams(i).name is not in lstTeams.Items Then lstTeams.Items.Add(teams(i).name) End If
I have a program that compiles and works so far, except for the above problem and my alphabetical order (which I can probably figure out on my own:
Public Class danbrockteams Structure team Dim name As String
[Code]....
This works except that my listbox is filled with the team every player is in rather than just listing all possible teams. Not exactly looking for someone to just give me the answer, as I understand things best when figuring them out on my own, so I suppose a hint is what I'm really after.
Option Strict On Option Explicit On Imports System.Data.OleDb
[Code]....
And the registration part works fine, but my only problem is that if someone registers twice with the same email, it will create another cell in Access, causing me to have duplicates.
I am building a data based application using VB 2008 an SQL Express. I need to create textboxes on my form using code, (With & End With) method. I need a simple code string that will allow the app to check if the field to wich the textbox wil be databound is Nul, If so the textbox will not be created.
I have a field in a sql table that is of datatype numeric(9,0).I have a time field on my input screen that is type textbox.I want to insert the time (which is type text) into the numeric field of my table. Do I need to parse this data somehow? Or will it just work as a text field? How would I do that?
I've got this code. But I keep getting an INSERT INTO error when I try to insert a new field into the database
Private Sub btnSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubmit.Click Dim recordsadded As Integer Dim strSQLString1, strSQLString2, strSQLString As String strSQLString1 = "INSERT INTO tblParts (PartName, PartPrice, Part Supplier) " [Code] .....
My 3 datatypes are text values, and I have another form adding entries to my database in another table, which are all text values.
When user inserts a duplicate entry in a unique field, Castle ActiveRecord throws the following exception: Castle.ActiveRecord.Framework.ActiveRecordException was unhandled Message="Could not perform Save for SerieNotaFiscal" Source="Castle.ActiveRecord" StackTrace: [Code] .....
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:
[Code]...
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!
I am creating a database in VB.NET for a movie rental place. I currently have three forms;
Member Information DVD Information Borrow DVDs
What I would like to do is when I am viewing a member's details, if I click a button 'Borrow DVD for Member', the member's ID number transfers over to the Borrow DVDs table in the Member ID which also would hold some information from the DVD Information table, but I'm sure if i can figure out how to do this firstly, I will be able to apply the same rule and work it out myself.I have been trying to use a query statement like;
INSERT INTO [Borrow DVDs].[Member ID] [IN goodstuffvideos.mdb] SELECT [Member Information].[Member ID] FROM [Member Information]
but that has been coming up with error codes and completely not working.
Borrow DVDs table fields are: Borrow ID, Member ID, DVD ID Number, Hiring Fee, Borrowing Limit?
DVD Information table fields are: DVD ID Number, Title, Rating, Hiring Fee, Borrowing Limit Member?
Information table fields are: Member ID, Family Name, Given Name, Address, Town/Suburb, Postcode?
The error coming up is; Error in INSERT statement. Unable to parse query text.And under that it says The query cannot be represented graphically in the Diagram and Criteria Pane.
I have a couple of textfields in a Windows form. One of these textfields is allowed to be NULL. When I enter a value for every field, it is all inserted, no problem. When I leave the field (txtGewicht) blank, I can't seem to be able to insert NULL in Access Database.
If Double.TryParse(txtGewicht.Text, 0) Then klant.Gewicht = Double.Parse(txtGewicht.Text) Else
[Code]....
This is what I get:
"Cannot set column 'Gewicht' to NULL, please use DBNull instead"
So I changed 'Nothing' to DBNull.value, but it then tells me that System.DBNull cannot be converted to type Double.
I have three dropdownlist which values are to be inserted in one particular field in the database. But i am new to ASP.
This are my following codes: Dim strConn = ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString Dim myConn As New SqlConnection(strConn)
I want to insert (store) a Word 2007 document into an SQL database field. I've previously done this with PDF files into an 'image' datatype field without problems. I can add the original document and retrieve it for viewing using Filestream as follows:
To add the file (where 'strPdfFile' is the file and 'myImageBuffer' is added to the field) Dim myStream As FileStream = New FileStream(strPdfFile, FileMode.Open, FileAccess.Read)
[Code].....
This also works with a Word .doc file (substituting the file extension). With a .docx file however, when taking the ByteArray back out of the database and re-creating the document, there is a problem opening it with Word 2007. An error message says the file is corrupt but offers to recover the file, which it does successfully.
I know docx is OpenXML but in this case I'm not interested in the data structure (as such), I just want to store it. I guess I should be using a different method (Serialization?) but not sure which. I would also like to keep the field DataType (image) if I can.
I have a textbox that acts as a password field. It is supposed to contain a value at least 8 characters long and not greater than 12 characters in length. I need to construct an if statement that checks to see if there is at least 1 numeric character in the string and at least one letter in the string.
I am attempting inserting into an Access database, and the insert is successful (when I open the database the data is there), but I'm getting an error: "The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and try again."
This is really confusing me. No matter what I insert, it still gives me the same error. And I don't understand why it's giving me an error even though it's working. Here's my codebehind:
Protected Sub Wizard1_FinishButtonClick(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.WizardNavigationEventArgs) Handles Wizard1.FinishButtonClick
I am attempting inserting into an Access database, and the insert is successful (when I open the database the data is there), but I'm getting an error: "The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and
I currently have this working already for one of my combo box's, but when i try to use the same code i get this error ''There is no row at position 6.'' . The are 2 fields in the table asset_type_id, asset_type_name', im trying to dispaly the values in a combo box for the field 'asset_type_name.
the code for ' Friend Sub RetrieveCustomerInformation2()' works but the other friend sub throws the error. Imports System.Data.SqlClient Imports System.Data Imports System Imports System.Data.OleDb
