i tried this sqlcommand select max(food) from foods and i tried this dim x as double=cdbl(cmd.executescalar)and it throws the the exception {System.Invalid CastException}because the food table is empty and the max(food) is null how can i fix that because i want to take the value and add one to it so do i need to catch the error or try another conversion option?
View 2 RepliesI have a Stored Procedure which returns 10 columns of data. Using cmd.ExecuteScalar() returns the value of the 1st column from the 1st record. How can I change this so that I can return different columns, by specifying their alias/dataitem name?
I want to be able to do something like: Dim FirstName as String = cmd.ExecuteScalar("FirstName")
show me how to do an insert with EF4 VB and also how to return the ID of the inserted row?This is what I have got for edit and it works.. I have seen some very confusing ways of doing selects and edits and have found that i'm most comfortable keeping it written nice like this so that I can go back and understand what I have done.
[Code]...
I want to insert a new order with an order_id and value for ExportedToOW and get the order_id back which is auto generated by the DB..
currently, I use this code:
[Code]...
I have an sp that deletes a bunch of rows and returns the number of rows deleted...
ALTER PROCEDURE [dbo].[DeleteChangeLog]
@ChangeEntityType bigint,
@StartDate datetime,[code]......
I have a stored procedure that repeats a block of T-SQL statements using WHILE logic until it finds a matching record in a table. When I execute the procedure directly from the SQL Management Studio, it works and returns a record, even when the statements within the WHILE logic have to be repeated over and over again before a matching record is found.
However, when I use the same stored procedure as the commandtext property of an sqlcommand object in Visual Studion 2008 (VB) and call the executereader method of the sqlcommand, the resulting SqlDataReader will only return a row if the T-SQL statements within the WHILE logic find a matching record after a single pass. If it takes more than one pass to find a matching record the SqlDataReader does not return a row. It's like it abandons the execution of the stored procedure after the first pass of the statements within the While logic, disregarding the repetition.
I'm calling Sqlcommand.ExecScalar() - stepping through the stored proc works fine, right under
RETURN @RecordNum
@RecordNum correctly contains a bigint, as scoped. When I step into the RETURN.. I get an exception thrown, that visual studio does not seem to be able to capture.
The stored procedure works fine when executed directly, and returns a value without problem, and it seems like all is well, stepping through it from my code.
But as soon as I step into 'RETURN @RecordNum' (and recordnum contains a valid number..) BOOM! EXCEPTION! (and no details in the exception either back in visual studio.
I'm blaming a glitch in the matrix.
I've turned off even assigned the return from the ExecScalar to anything, same result.. I've tried ExecReader(), same result. I have turned NO COUNT on and off, same result. If I wasn't already bald, I would be now!
I have dates I am reading from a database, when I format the dates and there is a blank date I have a dbnull error...
What is the correct syntax to say
IF txtOrderDate = DBNull
then
txtOrderDate = ''
ElseIf
txtOrderDate <> DBNull (return the formatted date)
' Populate Header
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I am working on a login page for an asp.net application. I'm making my own login and everything is working so far: I get a connection, the query is asking to return Count from the table where the username and password match the username password in the table.
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It worked fine till i applicated some conditions... Now my form execution stop right after a ExecuteScalar.[code]
View 2 RepliesWhy i got this error ?? ExecuteScalar: Connection property has not been initialized
the red section got error.
my code
Dim sql As String
Dim sql1 As String
Dim sql2 As String
[Code].....
I've got this
Public Function VendorIdOf(ByVal SimpleId As String) As String
Dim result As String = Nothing
Using drc As New SqlCommand("Select VendorId From Vendor_T Where SimpleId = @SimpleId", _connection)
[Code]....
"Object reference not set to an instance of an object."
Why is that? I would expect a null value to be returned if the row does not exist.
Also - out of curiosity - how come this can be written two ways?
result = drc.ExecuteScalar().ToString()
or
result = drc.ExecuteScalar.ToString
What's up with those paren's?
In my ASP.Net Web-Application, I'm getting this error: Conversion from type 'DBNull' to type 'Boolean' is not valid.
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I'm trying to get the AutoID after inserting a record in to a DB. Does this code look right as Mydata is blank afterwards?
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I have a big stored procedure that I run. At the end its supposed to select a singe value to say if it succeeded or not, so I run the query as
Dim Command As New SqlCommand(SqlString, Conn)
Return Command.ExecuteScalar()
Which works. However there is an error in my stored procedure. I know its causing an error because the logic in the stored procedure rolls back the transactions, and after the Execute Scalar call, my transaction count is down to 0 and the my data hasn't changed. However no SQL exception was generated.
The strange part is, I changed the code to grab all the result sets from the SP to see if I could get more information. So I called the same SP like this,
Dim DAObj As SqlDataAdapter = New SqlDataAdapter
Dim CommandObj As SqlCommand = New SqlCommand(SQLString, Conn)
DAObj.SelectCommand = CommandObj
Dim DS As New DataSet()
DAObj.Fill(DS)
When I run this, with the exact same sql as before, executing the exact same stored procedure, this time I get an SQL exception because one of my nested SP calls was missing required parameters. So what could cause this? Why would running it one way produce an error and the other way have the error but not report it? Is the difference on purpose, or some kind of obscure bug in ADO.Net?
How do I implement the ExecuteScalar method to return the first element in a sorted dataset?
Here is my code:Imports System.Data.OleDb
Sub Dim oCmd As OleDbCommand
Dim strConn As String
Dim strQuery As String
strConn &= "Provider=Microsoft.Jet.OleDb.4.0;"
[Code]...
i want to compare a column present in the access database BankAccount table with a field present in the form named as account......
[Code]...
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Is this possible to run 2 SqlCommand together??
Because after executed somehow the 2nd inside the loop did not execute or insert data.
I have an SqlCommand with parameters. Due to some external requirement (see PS), I need one T-SQL string instead, i.e., I need ... @parameter ... replaced by ... the-value-of-@parameter-encoded-correctly ... (e.g. O'Brien --> 'O''Brien', 02 Mar 2010 --> '20100302', 3.5 --> 3.5).
I know that I could home-brew such a solution quite easily, but correct escaping is tricky (make sure you get the right date and number formats, watch for quote signs in strings, etc.), and I guess that I'm not the only one needing this, so my question is:
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In order to check if specific user is db_owner, i excute the following query:
"select is_rolemember('db_owner', '" & p_userName & "')"
using the SqlCommand ExecuteNonQuery method.How do I get the query result?
Here is my code:
Dim com As SqlCommand = New SqlCommand(sql, m_connection)
com.ExecuteNonQuery()
[code].....
I am encountering a strange problem when attempting to execute a DELETE query agains a SQL Server table using VB.NET, SQL Command, and Parameters.
I have the following code:
Try
sqlCommand.Transaction = transaction1
sqlCommand.Connection = conn
[Code]....
Below is an UpDate Statement I am practising with David Sceppa's book ADO .NET 2.0 Core Reference pages 467 - 468. I can supply the parameter values for "parameter_New" by doing something like:
da.UpDateCommand.Parameters("@OrderID_New").Value = myTextBox.Text
And so on...My problem is how to supply the value of "paramete_Old" to be able to compare before update. I gues it has to do with obtaining the Original values of the rows based on RowVersion but I don't know how to effect it.
strSQL = "UPDATE [Order Details] " & _
"SET OrderID = @OrderID_New, ProductID = @ProductID_New, " & _
"Quantity = @Quantity_New, UnitPrice = @UnitPrice_New " & _
[code]....
I am experiementing with table updates and the code below gives me the following error message: "The variable named "@Processed" has already been declared... at the following code line: clsWTAdapter.Update("clsWTDataTable"). I fear that all of my code is a general mess, and I am sure there is a much better way to go about it.
Dim clsCmd As New SqlClient.SqlCommand
Dim clsCMAdapter = New SqlClient.SqlDataAdapter("SELECT * FROM CatalogMaster WHERE Processed <>-1", clsCnn)
Dim clsCMDataTable = New DataTable("CatalogMaster")
[code]....
[code]in this code, do the objects con and cmd get disposed because the return statement is placed before the end using statement.
View 1 RepliessqlCmd.Parameters.Add(New SqlParameter("@DateCreated", SqlDbType.DateTime)).Value = CDate(Now)
it throws error. Kindly suggest how can I assign date to sqlcmd parameter.
If there an easy way to get a completed SQL statement back after parameter substitution? I.e., I want to keep a logfile of all the SQL this program runs. Or if I want to do this, will I just want to get rid of Parameters, and do the whole query the old school way, in one big string? Simple Example: I want to capture the output:
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I am almost finished building my application. All the data need is being inputted from various locations. I have a form that is suppose to consolidate all this data into a specific format. There are 47 fields that have to be populated and/or calculated based on two fields, the Username and a date range (this part is done). I was trying to set each of the TextBoxes equal to the SQLCommand that would return the proper value, but i am not calling it correctly. Would somebody please take look, is there something i am missing, do i need to write it in a function? I have had to use the Select statement itself in a couple of filters so I'm pretty sure that is correct, but i need help getting it to run the sqlcommand.[code]
View 16 RepliesAfter the SQL Publishing Wizard has generated a database script I would like to know if it would be possible to execute the whole SQL script using the SqlCommand object, to recreate the database all over again, in case anything goes wrong?
View 8 RepliesI have a VB.net script that runs a simulation on several machines within the domain. During this simulation, a login is initiated to an application via a web portal. After the login, the connection to a specific Citrix server (whichever is least busy) is established. At this point, I want to run a Netstat -r | find (IP Range of server farm) in command line. From what I have deduced, I probably won't be able to do what I want from the command line and everything will have to be with in the VB.net module using System.Net.NetworkInformation. I am a Citrix Administrator with a decent level of .net experience but I am having trouble with this.
View 4 RepliesIn a for each loop I am adding rows to a table for a cross reference. Using the following code:
For Each cp In pCheckPoints
If cp <> String.Empty Then
Dim insertSQL As New StringBuilder
With insertSQL
.Append("INSERT INTO [CheckpointMessage] ( ")
Without the objCommand.CommandText = String.Empty line the CommandText is appending the insertSQL but that doesn't make any sense to me because I would expect the objCommand's commandText to be empty since it is in a using block.