At the moment when a user logs into my system it checks to see if a job exists, if so the records are put into a datagridview. However, if there are no jobs in the database I get an error.
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I am using VS 2008 and MySQL. Which one of the following methods is efficient or a proper one to check if record exists or not before making an attempt to insert.
1. HasRows Property.
2. Select Where Exists
3. Select Count(*)
Or if there is any other appropriate method ( which i am not aware of ) available to do it in vb.net ?
i can't find any wrong, if record exists then updated the record but only can insert the new record.
cannot updated the record.why?
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Basically i have a form with a sqldataadapter and a dataset to retrieve and process data. from within the form i call another form which i use to retrieve data given some criteria which my user enter (on the secord form i also use a sqldataadapter and dataset.my problem is this: the use can select 1 or more records from the second form which he or she wants to process and the logic is to jump back to the first form and show only those records. note: the secord form (search data form) can display any number of records
View 1 RepliesI have a small database. 2 main tables called CaseDetails and Checks.Each record in CaseDetails can have 3 checks recorded against it in the Checks table. But can only have one check of each type (check types 1, 2, 3).I have 3 linkbuttons which will take the user to the input form for each 'check'. If a 'check' already exists i want to hide the linkbutton that takes the user to that 'check type' input form (the 3 input forms have different fields).So what i need to do, is connect to the SQL database and see if a record exists for each 'check type' and hide the linkbutton to prevent users from entering another record with the same 'check type'?I have tried reading the reults into an array and examining that array, but havent been able to do so.
View 5 RepliesI have a tenant details form that has a field called TenantID, I also have a Lease table that also has a TenantID field, what I want to do is click the lease button, check to see if the lease already exists, if it does open the lease form to that record. If not then open the lease form to a New record so the user can enter all the information for that lease.
I am trying to use the below code but am having a little trouble understanding how it all works. What needs to be declared, what doesnt
HTML
Private Sub btnLease_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLease.Click
Dim fm2 As New LeaseDetails
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Working on an VB/ASP website in Visual Studio 2008. Getting the error "You cannot add or change a record because a related record is required in table 'abc'
It is true that table xyz (the target of the INSERT) is in a parent-child relationship with table abc. The PK in abc is a column RequestID_lng. The FK column in xyz is also named RequestID_lng
This is the only relationship these 2 tables are in.
I am trying to add a row in xyz with a value of 45 in the FK. There is already, previous to this action, a row in table abc with a value of 45 in the PK. So the parent already exists for this child.
I have used the watch window to copy my SQL code for the INSERT query that is being executed. I pasted that code into a new query in the Access DB and executed it without problem - it actually added the row that .Net should have.[code]...
I am having a ton of trouble trying to check if a record exists. I continue to get a data mismatch on my command.ExecuteScalar().
Code:
Protected Sub btnRegister_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnRegister.Click
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I am importing alot of data from a text file into an access database with the code below. (From a Comma delimited text file) The problem is that I do not want to import duplicate records. I have the "IDNr" column in my access database set to "not allow duplicates" and need my code to check if there is already a record in the database before trying to import the data. Otherwise it will just give me an error or not import the rest of the data. I could do to make sure that there are no duplicates for the IDNr column?
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I have an default.aspx page that I'm trying to have redirect the user to a different page depending on whether or not their deviceId is stored in the SQL Server database. It should direct the user to the login.aspx if the record for the user is found or to the newdevice.aspx page if there was no record found. I want this to occur on Page_Load but have not been able to figure it out so far.
View 3 Repliesthe next code is working but when I try to insert an existing record, it gives me an error and I want to add a msgbox to let people now that the username is already taken.Only the username cannot repeat on the database because it's the primary key.. the rest of the table rows can repeat.
Dim cn As New OleDbConnection
cn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Fabio\Desktop\Telemoveis\Telemoveis\Db_Tel.accdb"
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I'm updating an app for children I wrote in VB6 to VB2010. It uses a rather extensive MSAccess Database. It works perfectly but I need to update it to utilize better speech technology. I have read a lot about SQL and can't find how it is useful for anything accept business applications that add, delete or update records as long as you hard code in a name. I don't use datagrids and I never display a table. how to do a few things, I can figure the rest out.
In VB6, I had:
Option Explicit
Public db As Database
Public rs As Recordset
Public Reader As Recordset
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If you have been reading my posts I'm trying to learn this ADO.net code. So I have been reading and coding and I have a Question. How to I know in .net, if the record exists to make the decision to Add New Row or UpdateRow? Here is the code from the web I have been working with to better understand this, I could use some help on the decision making code needed to Update or New row.
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I declar a dataset in my setting i Write the code below:
GlobalDataSet = My.Settings.GlobalDataSet
GlobalDataSet.Tables.Contains(TableName)
But problem is when load my application first time My.Settings.GlobalDataSet is null. a error rise in secound line is NullReferenceException. i try to write below:
If
My.Settings.GlobalDataSet =
""
Then
GlobalDataSet = My.Settings.GlobalDataSet[code]....
but it say sindex error. is there any code for check My.Settings.GlobalDataSet is null or not null.
I am having very odd behaviour from my compiler when i run my program, i have two practically identical snippets of code that are doing pretty much the same thing: both are populating nodes on a treeview using information from the treenode above but when the program runs one of the snippets tells me at runtime that something i have defined is nothing. [code] section and title are columns in a dataset defined by dtName that exists, and the where bit is refering to a column where the entries match the value assigned to volume. which is 1 in the first iteration.
View 2 RepliesI have the following code which goes to the next available record to process.
Dim ds As New DataSet
Dim strListType As String = Request.QueryString("ListType")
Dim strStatusFilter As String = ""
Select Case strListType
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ObjClass.List is a method which is implemented to run a view and filter out data. I am ordering data on two columns due_dt and joined_dt. My problem is that it goes to the same record everytime if I didnt update my due date. I just want to go to the next record if am not updating it. Ho can I have the behaviour I want? what changes I can make?
the code is below. the system said me that the insert into sql syntax error
Dim dbProvider As String
Dim dbSource As String
Dim constr As New OleDb.OleDbConnection
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I have customer/order form.When i delete a record from datagrid.It deletes the record but when i refresh the page or run the app again it comes because i think it just deletes temp from the grid not from the database.How do delete it from the database?[code]...
View 2 RepliesI have a dataset column which is "newsID".I want to get the value of it's last record so that I can use it as a default value or starting point to auto increment when I add a new record using the BindingNavigator.
View 1 RepliesSyntax error: Missing operand after 'top' operator.on line below dg.DataSource = dsResult.Tables("aTable").Select("RowID in (select top (100) [RowID] from aTable)")
Does anyone other way to do this.
BTW the rowID is just a unique id.
I am having the same problem <as this >> when i update my record in Access Database. It is successfully updated the record in the database. but the dataset in my project is still not updated. I am using vb 2005 to develop the application.
View 2 RepliesHow to find record on a table using dataset?
View 2 RepliesI have finally taken the plunge and am trying to get my head around VB 2010 after years of playing with VB6. I am using the free VB 2010 Express edition to get me started I am not an acomplished programmer in VB6 - being totally self taught from books, files , forums like this and internet searches so I am finding the transition to .NET syntax very painfull. Unfortunately,
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I am trying to add a record to a typed dataset using example code provided on msdn. Currently using VS 2010 Ultimate (Trial until box arrives) Visual Basic Windows Forms Project. Unfortunately I am having a bit of trouble.[code]....
View 7 RepliesI am trying to insert a new record into msaccess2003 mdb file my version is VB.net 2005, it doesnt show any error and also when i open my access db file, there is no record inserted, And also how can i format the date field it is giving me error, how can i convert the txtdate.text to date compatible with ms acess.[code]
View 1 RepliesI am trying to ping a list of IP's that reside in a dataset
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I have a VS2010 VB application using a SQL Server 2008 R2 database. I display a record in a form and allow the user to update the record and save the changes. However, the changes don't make it to the table. Here's the sample code for the Save button click[code]...
View 5 RepliesBelow mentioned codes I used in VB 0.6, now I want to use the same codes in VB.NET Windows Form (VS2010)
With EMPrecordset
EMPrecordset.MoveFirst
Total = EMPrecordset.Fields("OT")
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For j = 0 To wcData.Tables(0).Rows.Count - 1
For i = 900 To 1700
wcData.Tables("db").Rows(j)("range") = i
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trying to insert "i" into each column cell of "range"
i have a situation where I need to search a table for a specific record that matches an ID number the user will specify. I know 2 methods to accomplish this. The first would involve writing some VB.net code that would call a TSQL statement and return the value through the return parameter. The second method would involve creating a dataset and populating it with a select statement.
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