I will try to keep this as brief as possible.
I have a function called GetData(ByVal query As String) whose sole purpose is to populate a data table multiple times based on certain conditions. As you can see, the function accepts a string variable where the SQL statement resides. What I am trying to do is add a scalar variable, "#date" in my case, and no matter where I try to add this variable it throws an error stating "Must declare scalar variable #date.
Edit: I should mention that it is throwing the "must declare variable" error on the sda.Fill(dt) line.
GetData Function
Private Shared Function GetData(ByVal query As String) As DataTable
Dim constr As String = ConfigurationManager.ConnectionStrings("WarrantyConnectionString").ConnectionString
Using con As SqlConnection = New SqlConnection(constr)
Using cmd As SqlCommand = New SqlCommand(query)
Dim dt As DataTable = New DataTable()
cmd.Parameters.Add("#date", SqlDbType.Date).Value = Date.Today
Using sda As SqlDataAdapter = New SqlDataAdapter(query, con)
cmd.Parameters.AddWithValue("#date", Date.Today)
sda.Fill(dt)
End Using
Return dt
End Using
End Using
End Function
I am calling the function in a procedure that has the query and handles all of the conditions I need.
Procedure
Dim queryStart As String = "SELECT ( SELECT SUM(DealerNet) FROM Agreement WHERE VoidDate IS NULL "
Dim queryAlias As String = "AS Actual, "
Dim queryStart2 As String = "(SELECT SUM(Amount) FROM AccountingUS.dbo.ProjectedSales "
Dim queryAlias2 As String = "AS Projected "
If chart = "pmtd" Then
Dim queryCondition As String = "AND IssueDate BETWEEN (SELECT DATEADD(MONTH, DATEDIFF(MONTH, 0, #date)-1, 0)) AND #date) "
Dim queryCondition2 As String = "WHERE [Month] = MONTH(#date) AND [Year] = YEAR(#date)) "
Dim query As String = queryStart + queryCondition + queryAlias + queryStart2 + queryCondition2 + queryAlias2
Dim xMember1 As String = "Actual"
Dim xMember2 As String = "Projected"
Dim dt As DataTable = GetData(query)
pmtdChart.DataSource = dt
The variable in question is the #date variable in the strings within the "If" statement, the only value it holds is todays date. Currently, I have tried to use "cmd.Parameters.Add("#date", SqlDbType.Date).Value = Date.Today in the GetData function, however, I still receive the same "Must declare scalar variable" error. I have also tried replacing the #date variable with simply "" + Date.Today + "" or a variable that holds todays date, but upon doing so I receive an operand error about "Operand Clash: Date is incompatible with Int"
Any help regarding this issue would be greatly appreciated, I am relatively new to programming and would appreciate any tips or criticisms regarding best practices. If you need any additional information or clarification regarding this issue I would be happy to provide what I can. Thank you in advance.
Ok, a few things:
I would actually pass a command object to that get data routine.
And your issue is you feeding the query to the "adaptor", but NOT supplying the #date parameter to that "sda"
this:
Using sda As SqlDataAdapter = New SqlDataAdapter(query, con)
cmd.Parameters.AddWithValue("#date", Date.Today)
sda.Fill(dt)
End Using
In other words, you NOT EVEN using the cmd object!!!
So, you would need to add the parameter's to the sda object!!
eg this:
Public Function GetData(ByVal query As String) As DataTable
Dim dt As DataTable = New DataTable()
Dim constr As String =
ConfigurationManager.ConnectionStrings("WarrantyConnectionString").ConnectionString
Using con As SqlConnection = New SqlConnection(constr)
Using sda As SqlDataAdapter = New SqlDataAdapter(query, con)
sda.SelectCommand.Parameters.Add("#date", SqlDbType.Date).Value = Date.Today()
sda.Fill(dt)
End Using
End Using
Return dt
End Function
So, yes, you WILL get that error about "#date" not being declared, since you NOT using the cmd object to fill the table, but are using the data adaptor.
So, as a future suggest?
Pick one way, or the other way.
I MUCH over the years have decided that I will use/have/adopt and cookie cut over and over the SqlCommand object.
I find the Sql cmd object better, since:
it has the parameters.
it has a connection object (if you want to use)
it has a data reader built in
So, what this means?
I suggest this code for get data:
Private Shared Function GetData(ByVal query As String) As DataTable
Dim constr As String =
ConfigurationManager.ConnectionStrings("WarrantyConnectionString").ConnectionString
Dim dt As DataTable = New DataTable()
Using con As SqlConnection = New SqlConnection(constr)
Using cmd As SqlCommand = New SqlCommand(query, con))
con.Open()
cmd.Parameters.Add("#date", SqlDbType.Date).Value = Date.Today
dt.Load(cmd.ExecuteReader)
End Using
End Using
Return dt
End Function
So, we don't need a data adaptor. In fact, you only need a adaptor if you going to update the resulting table (think a "adaptive" table to remember this). You not going to update the data, so really, no need to use a "adaptor" at all here. (and sadly, far too many examples use a "adaptor" anyway. They are for ALLOWING update of the data table, and you not doing that!
So, use a command object. Do note that you ALWAYS must then open the confection, but since we have "using" blocks, it will ALWAYS be closed for you.
And note how then we don't create to "use" the "reader" from the adaptor, nor a fill command. (so, we eliminated one whole confusing object!!).
So, in your example, you created a SQL command object, correctly added the parameter to the command object, but THEN DON'T use it, and then decided to create a data adaptor, and use that!!!
So, you could/can leave your code as you had with the sda "prameter " fix I posted above.
However, but I think your better off to use a sql command object.
Note even better?
Pass the command object to the GetData routine.
I have a global "general" purpose routine called MyRstP(), and I pass it a command object, even for just plain jane sql.
but, if you decide to add parameter's, you can!
Do note that parameter's can be added 100% independent of the SQL string, and they can be added before, or after you set the sql string.
And you can add parameter's WITHOUT a valid working connection (or have created one just yet). So, "parameters" are just a colleciton - it does not care about the SQL (well, at least not yet!!).
So, here is my RstP, and I dumped this into a plain jane "module1" which VB has (this means you don't have to create a static class, and this works then just like VB6, or VBA.
So, this:
Public Function MyRstP(cmdSQL As SqlCommand, ByVal Optional strCon As String = "") As DataTable
If strCon = "" Then
strCon = My.Settings.TEST4
End If
Dim rstData As New DataTable
Using conn As New SqlConnection(strCon)
Using (cmdSQL)
cmdSQL.Connection = conn
conn.Open()
rstData.Load(cmdSQL.ExecuteReader)
End Using
End Using
Return rstData
End Function
So, now to say fill a grid view, I use this:
Dim strSQL As String =
"SELECT id, HotelName, City FROM tblHotelsA"
Dim cmdSQL As New SqlCommand(strSQL)
GridView1.DataSource = MyRstP(cmdSQL)
GridView1.DataBind()
or say a given date of some such:
How about all hotel visit dates from start of year.
So, this:
Dim strSQL As String =
"SELECT id, HotelName, City FROM tblHotelsA
WHERE VisitDate >= #dtStart"
Dim dtStart As DateTime
dtStart = DateSerial(DateTime.Today.Year, 1, 1)
Dim cmdSQL As New SqlCommand(strSQL)
cmdSQL.Parameters.Add("#dtStart", SqlDbType.DateTime).Value = dtStart
GridView1.DataSource = MyRstP(cmdSQL)
GridView1.DataBind()
note then how I have that MyRstP (like your get data), but I can pass it quite much anything I want, including parameter's from the "calling" code, NOT in that general routine.
Anyway, the above use and adding the parameter's to the "adaptor" will fix this, but I would change over to using just a command object and a connection - the adaptor really not required, and as noted, they really are to be used WHEN you actually want to update the data table, and then send it back to the database in one shot.
If you look closely, you setup a cmd command, but you never actually pass it to the DataTable. So it doesn't know anything about your params.
How about this instead (copied untested from Trying to pass SqlCommand in SqlDataAdapter as parameters):
DataTable dt = new DataTable();
using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings("WarrantyConnectionString").ConnectionString))
{
con.Open();
using (SqlCommand cmd = con.CreateCommand())
{
cmd.CommandText = query;
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add("#date", SqlDbType.Date)
cmd.Parameters.AddWithValue("#date", Date.Today)
using (SqlDataAdapter adp = new SqlDataAdapter(cmd))
{
adp.Fill(dt);
return dt;
}
}
}
Dim dt as new DataTable()
using db as new SqlConnection(ConfigurationManager.ConnectionStrings("WarrantyConnectionString").ConnectionString)
db.Open();
using cmd as New SqlCommand(query, con)
cmd.Parameters.Add("#date", SqlDbType.Date).value = Date.Today
//cmd.Parameters.AddWithValue("#date", Date.Today)
using adp as new SqlDataAdapter(cmd)
adp.Fill(dt)
return dt
End using
End using
End using
I'm having an issue, I'm calling a procedure on oracle 11g, the prucedure receives a clob and responds with a different CLOB, a VARCHAR2 and a Number. The procedure is called from a ASP.NET (on Visual Basic) webpage using oracle data provider (ODP.NET), I can call the procedure successfully, view the VARCHAR2 and NUMBER returned values, but when I try to see the returned value of the returning CLOB all I get is "Oracle.DataAccess.Types.OracleClob" instead of a expecting XML
I know the returned XML is generated because on the store procedure I create a txt file where it shows the expected result
My code it's pretty simple right now:
Function Index() As String 'ActionResult
Dim xml_message As String
Dim oradb As String = "Data Source=127.0.0.1;User Id=id;Password=pass;"
Dim conn As New OracleConnection(oradb)
Dim oracleDataAdapter As New OracleDataAdapter
oracleDataAdapter = New OracleDataAdapter()
Dim cmd As New OracleCommand
cmd.Connection = conn
cmd.CommandType = CommandType.StoredProcedure
cmd.CommandText = "Common.GetDriverPoints"
cmd.BindByName = True
Dim driver_input As New OracleParameter()
driver_input = cmd.Parameters.Add("p_driver", OracleDbType.Clob)
driver_input.Direction = ParameterDirection.Input
driver_input.Value = <THE_SENDED_XML_VALUE>
Dim driver_output As New OracleParameter()
driver_output = cmd.Parameters.Add("p_output", OracleDbType.Clob)
driver_output.Direction = ParameterDirection.Output
Dim error_flag As New OracleParameter()
error_flag = cmd.Parameters.Add("p_Return", OracleDbType.Int16)
error_flag.Direction = ParameterDirection.Output
Dim error_desc As New OracleParameter()
error_desc = cmd.Parameters.Add("p_ReturnDesc", OracleDbType.Varchar2, 100)
error_desc.Direction = ParameterDirection.Output
conn.Open()
cmd.ExecuteNonQuery()
Dim output As String
output = driver_output.Value.ToString() 'This only returns Oracle.DataAccess.Types.OracleClob
conn.Close()
conn.Dispose()
Return output
End Function
Also, the generated xml is around 55Kb, sometimes it's bigger
Thank you
I manage to find the answer, In case someone have the same problem, basically what has to be done is create another clob, used only on for vb.net, that clob will receive the value of the parameter output from the procedure, then cast to a string variable the local clob.
Example:
Dim output As String
Dim myOracleClob As OracleClob = driver_output.Value
output = System.Convert.ToString(myOracleClob.Value)
Now the "output" variable holds the actual message of the clob.
Hope this helps anybody with the same problem.
We have a WebMethod created in an ASP.NET 2.0 Web Service (VB), which is accessed throughout the application very frequently. The WebMethod gets the query as a parameter and returns the DataSet. It works fine when the number of users is 1 or 2. If ~30 users are using the system simultaneously, the WebMethod returns the DataSet of a different query. We have tried the synclock (lock in C#) option, but it does not work.
Public Function ExecuteQry(ByVal StrText As String) As DataSet
Dim AdoDs As New DataSet()
Dim SqlDp As New SqlDataAdapter
Dim SqlCmd As New SqlCommand
Dim SqlParam As New SqlParameter
Try
SyncLock AdoDs
MakeConnect()
With SqlCmd
.Connection = SqlCon
.CommandText = "rExecuteQry"
.CommandType = CommandType.StoredProcedure
End With
SqlParam = SqlCmd.Parameters.AddWithValue("#strText", Trim(StrText))
SqlDp.SelectCommand = SqlCmd
SqlDp.Fill(AdoDs)
DisposeConnect()
Return AdoDs
End SyncLock
Catch ex As SqlException
DisposeConnect()
Debug.Write(ex.Message)
Finally
SqlCmd = Nothing
SqlParam = Nothing
End Try
End Function
Below is the stored procedure:
ALTER PROCEDURE [dbo].[rExecuteQry]
#strText Varchar (max)
as
Exec( #StrText)
I'm having a problem populating a child gridview using a function I define. I keep getting the error "Object reference not set to an instance of an object". What am I doing wrong? Am I using the FindControl function incorrectly? It doesn't seem to find the child gridview.
Sub RecordsByZip()
Dim DBConn As New SqlConnection(Application("DBConn"))
Dim gv1 As GridView
gv1 = grdTotal
Dim gv2 As GridView
gv2 = DirectCast(gv1.FindControl("grdChild"), GridView)
Dim ZipCode = lbZip.SelectedItem
For Each ZipCode In lbZip.Items
If ZipCode.Selected = True Then
Dim cmdZip As SqlCommand = New SqlCommand("spPICAInsertTotals2", DBConn)
cmdZip.CommandType = CommandType.StoredProcedure
strZip = ZipCode.Text
strUser = Session("User")
Dim Zip As New SqlParameter("#Zip", SqlDbType.VarChar)
Zip.Value = strZip
cmdZip.Parameters.Add(Zip)
Dim UserID As New SqlParameter("#UserID", SqlDbType.Int)
UserID.Value = strUser
cmdZip.Parameters.Add(UserID)
DBConn.Open()
gv1.DataSource = cmdZip.ExecuteReader
gv1.DataBind()
gv1.Visible = True
DBConn.Close()
End If
Next
btnExport.Visible = True
lblmsg.Visible = False
' Dim DBConn = New SqlConnection(Application("DBConn"))
Dim cmdCounty As SqlCommand = New SqlCommand("spPICAInsertTotals", DBConn)
cmdCounty.CommandType = CommandType.StoredProcedure
'Dim gv As GridView = TryCast(e.Row.FindControl("grdChild"), GridView)
strUser = Session("User")
Dim UserID2 As New SqlParameter("#UserID", SqlDbType.Int)
UserID2.Value = strUser
cmdCounty.Parameters.Add(UserID2)
DBConn.Open()
gv2.DataSource = cmdCounty.ExecuteReader
gv2.DataBind()
gv2.Visible = True
DBConn.Close()
btnExport.Visible = True
lblmsg.Visible = False
lblInstructions.Visible = False
End Sub
First of all . . .
Just as a disclaimer, I normally use repeater controls instead of gridview controls.
But this may help you . . .
I can tell you that with repeater controls, if you want to find a nested repeater then you must look for them inside the item of the parent repeater to which they belong. Essentially, what you are trying to do with the code above, is find grdChild when there might actually be several grdChild (it is a nested gridview, after all). I'd be willing to bet this is where you're object reference error is occurring.
In other words, if you want to find the nested repeater with the ID nestedRepeater, and you know it is located in the first item of your main repeater (which in this case I've assigned to the myRepeater variable), you can do this:
Dim myItem as RepeaterItem = myRepeater.Items(0)
Dim Rep2 as Repeater = myItem.FindControl("nestedRepeater")
Using SqlDataAdapter and a DataSet (recommended)
Dim sa As New SqlDataAdapter(cmdCounty) 'Initialize the SqlDataAdapter and assign the SqlCommand object to it.
Dim ds As New DataSet() 'Initialize the DataSet (we will bind this to the gridview)
Try 'The Try/Catch statements help you to handle errors.
cmdCounty.Connection.Open() 'Open the connection to the database.
sa.Fill(ds) 'This statement uses the SqlDataAdapter to easily execute the SqlCommand (using the query specified in the SqlCommand object) and . . .
'. . .use that data to fill our dataset.
cmdCounty.Connection.Close() 'These statement close the connection and dispose of the SqlCommand object. Note: You may only need the dispose command.
cmdCounty.Dispose()
Catch ex As Exception
'Catch your error here.
cmdCounty.Connection.Close()
cmdCounty.Dispose()
End Try
gv2.DataSource = ds 'Set the datasource for your GridView control.
gv2.DataBind() 'Bind the data.
Using SqlDataReader and a DataTable
According to your comment, you're code is breaking when you assign the gridview to the cmd.ExecuteReader.
You will need to access your data using a method like this:
Dim rdr as SqlDataReader = cmdCounty.ExecuteReader() 'Declare the SqlDataReader and set it to handle your SqlCommand.
Dim dt as New DataTable 'Initialize a new DataTable. This is where we will place the information we read using the SqlDataReader.
'Make sure you add the columns...
dt.Columns.Add("firstColumnName") 'Create a column for each field you will be retrieving data from.
dt.Columns.Add("secondColumnName")
Dim r as DataRow 'Declare the variable r as a DataRow.
'You may want to insert the line "If rdr.HasRows Then" to check if any data was pulled before attempting to read it.
While rdr.Read() 'Loop through each row in the reader.
r = dt.NewRow() 'Set r to equal a new DataTable in the DataTable we created. Note: This does not actually add the row to the table.
r("firstColumnName") = rdr("firstColumnName") 'Set the values of each column in the current DataRow to equal their corresponding data read from SQL.
r("secondColumnName") = rdr("secondColumnName")
dt.Rows.Add(r) 'Add the DataRow r to the DataTable.
End While 'Loop back until there are no more rows.
gv2.DataSource = dt
gv2.DataBind()
Both of these examples assume you have already created your SqlCommand object and have assigned a working SQL query string and Connection object to it.
I want to output some data to the user based on their username. This data is held in a table that is linked to the aspnet_Users table. I'm trying to write a sqldatareader as part of a function so I don't have to rewrite the code when it could be called from several pages. I know this is probably very simple buty I can't seem to access the data from outside the function. The function I have so far is as follows:
Public Shared Function AgencyDetails() As SqlDataReader
Dim details As String = "SELECT * FROM tbl_Relationships WHERE ContactSub = #Username"
Dim connString As String = ConfigurationManager.ConnectionStrings("ApplicationServices").ConnectionString
Using dbConnection As New SqlConnection(connString)
dbConnection.Open()
Dim cmdAgency As New SqlCommand(details, dbConnection)
cmdAgency.Parameters.AddWithValue("#Username", membership.getuser)
Return cmdAgency.ExecuteReader()
End Using
End Function
How can I call this function and access the information on my page? Something like the following?
lblAgencyDetails.text = AgencyDetails(0)
Thanks
The way you have it now, it won't work because you enclosed the connection in a using statement, by the time you return the Reader the connection will be closed and disposed so the reader won't be able to read anything.
What you should do in that function is load the info in a DataTable and return the datatable.
Example:
Public Shared Function AgencyDetails() As DataTable
Dim details As String = "SELECT * FROM tbl_Relationships WHERE ContactSub = #Username"
Dim connString As String = ConfigurationManager.ConnectionStrings("ApplicationServices").ConnectionString
Using dbConnection As New SqlConnection(connString)
dbConnection.Open()
Dim cmdAgency As New SqlCommand(details, dbConnection)
cmdAgency.Parameters.AddWithValue("#Username", membership.getuser)
Dim dt as new DataTable()
dt.Load(cmdAgency.ExecuteReader())
return dt
End Using
End Function
You can access the rows in the data table by doing:
For Each row as DataRow in dt.Rows
Console.WriteLine(row("ColumnName"))
Next
To be able to retrieve the data from the DataReader object, you should call the Read() method:
While reader.Read()
Console.WriteLine(String.Format("{0}, {1}", _
reader(0), reader(1)))
End While
This method moves the SqlDataReader to the next record.