I have a table with 9 records.
When I run SELECT * FROM table; in my VB.Net I only get 6 from the 9 records.
When I run the query in 'DB Browser' an SQLite viewer I get them all.
Here is my code:
Dim SQLconn As New SQLite.SQLiteConnection()
SQLconn.ConnectionString = connstring
If SQLconn.State = ConnectionState.Open Then SQLconn.Close()
Dim SQLcmd As New SQLiteCommand
Dim SQLdr As SQLiteDataReader
Dim SQLstr As String
SQLstr = "SELECT * FROM SignedEvent;"
SQLconn.Open()
SQLcmd.Connection = SQLconn
SQLcmd.CommandText = SQLstr
SQLdr = SQLcmd.ExecuteReader()
SQLcmd.Dispose()
While SQLdr.Read()
ListBox1.Items.Add(SQLdr("TotalTicketCounter").ToString)
End While
SQLdr.Close()
SQLconn.Close()
SQLconn.Dispose()
Related
I'm trying to update the records from textboxes into the Access database, I'm wondering every time I hit save, it generates an error
An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in System.Data.dll
Additional information: No value given for one or more required parameters.
Highlighting .ExecuteNonQuery()
What does it mean? It's preventing me to run my code :(
Private Sub SaveButton_Click(sender As Object, e As EventArgs) Handles SaveButton.Click
Dim empNum As String
Dim empFname As String
Dim empLname As String
Dim empDept As String
Dim empStat As String
Dim empYears As String
empNum = eNumText.Text
empFname = empFnameText.Text
empLname = empLnameText.Text
empDept = DeptText.Text
empStat = StatText.Text
empYears = yearstext.Text
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source= c:\Databse\Company_db.accdb"
con.Open()
Dim SqlAdapter As New OleDbDataAdapter
Dim Table As New DataTable
Dim sqlQuery As String = "UPDATE tbl_empinfo " & _
"SET FirstName=empFname, LastName=empLname, Department=empDept, " & _
"Status=empStat, Years=empYears " & _
"WHERE empID=empNum"
Dim cmd As New OleDbCommand
With cmd
.CommandText = sqlQuery
.Connection = con
.Parameters.AddWithValue("FirstName", empFname)
.Parameters.AddWithValue("LastName", empLname)
.Parameters.AddWithValue("Department", empDept)
.Parameters.AddWithValue("Status", empStat)
.Parameters.AddWithValue("Years", empYears)
.ExecuteNonQuery()
End With
Using cmd2 = New OleDbCommand(sqlQuery, con)
cmd.Parameters.AddWithValue("FirstName", empFname)
cmd.Parameters.AddWithValue("LastName", empLname)
cmd.Parameters.AddWithValue("Department", empDept)
cmd.Parameters.AddWithValue("Status", empStat)
cmd.Parameters.AddWithValue("Years", empYears)
cmd.ExecuteNonQuery()
End Using
sqlQuery = "SELECT * FROM tbl_empinfo "
Dim cmd1 As New OleDbCommand
Dim da As New OleDbDataAdapter
With cmd1
.CommandText = sqlQuery
.Connection = con
With SqlAdapter
.SelectCommand = cmd1
.Fill(Table)
End With
With DataGridView1
.DataSource = Table
End With
End With
con.Close()
End Sub
You are trying to set an UPDATE command text for the SelectCommand of the Adapter. This, of course has no way to be successful. Last but not least the UPDATE command text doesn't contain a WHERE clause, and so, if executed, it updates every record in the table tbl_empinfo with the same data.
In this context there is no need to use an adapter. You could simply execute the command, providing an appropriate WHERE clause and the values for the other parameters
Dim sqlQuery As String = "UPDATE tbl_empinfo " & _
"SET FirstName=?, LastName=?, Department=?, " & _
"Status=?, Years=? " & _
"WHERE empID=?"
Dim cmd As New OleDbCommand
With cmd
.CommandText = sqlQuery
.Connection = con
.Parameters.AddWithValue("#p1", empFName)
.Parameters.AddWithValue("#p2", empLName)
.Parameters.AddWithValue("#p3", empDept)
.Parameters.AddWithValue("#p4", empStat)
.Parameters.AddWithValue("#p5", empYears)
.Parameters.AddWithValue("#p6", empNum)
.ExecuteNonQuery()
End With
After this you could call the code that reloads the data to fill your grid
sqlQuery = "SELECT * FROM tbl_empinfo"
Dim cmd1 As New OleDbCommand
Dim da As New OleDbDataAdapter
Dim Table As New DataTable
With cmd1
.CommandText = sqlQuery
.Connection = con
With da
.SelectCommand = cmd1
.Fill(Table)
End With
With DataGridView1
.DataSource = Table
End With
End With
Notice that I have changed the name of the command and the adapter to a less confusing names. SqlCommand And SqlDataAdapter are the names of the classes equivalent to the OleDbCommand and OleDbDataAdapter but used for Sql Server. At first sight I was thinking that you were trying to use the SqlClient classes to update an MS-Access database.
I am retrieving records from a database with the following code.
Dim SearchID As Integer = teacherID
Dim NewStudentID As Integer = studentID
Dim DisplayTable As New DataTable()
Dim da As New OleDbDataAdapter()
Dim sqlquery As String = ("select * from tblAppointments WHERE TeacherID =" & teacherID & "")
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
Try
da.SelectCommand = New OleDbCommand(sqlquery, conn)
da.Fill(Finalds, "Display")
DisplayTable = Finalds.Tables("Display")
DisplayTable.Columns.Remove("Instrument")
DisplayTable.Columns.Remove("Room")
DisplayTable.Columns.Remove("TeacherID")
Registersgridview.DataSource = DisplayTable
Registersgridview.Columns(0).Visible = False
conn.Close()
Catch ex As Exception
MsgBox("There are no appointments in the database for " + Tutorcombox.Text)
End Try
It also there then added to a datagridview and certain columns are removed and some are hidden aswell.
Because its essentially a register, when the use clicks on the datagridview field that is a boolean it changes from false to true. I have been trying to send this back to the database, but have had no luck. I have tried the following :
Dim dt As DataTable = New DataTable("SendTable")
Dim row As DataRow
dt.Columns.Add("appID", Type.GetType("System.Int32"))
dt.Columns.Add("Present", Type.GetType("System.Boolean"))
For i = 0 To Registersgridview.Rows.Count - 1
row = dt.Rows.Add
row.Item("appID") = Registersgridview.Rows(i).Cells(0)
row.Item("Present") = Registersgridview.Rows(i).Cells(5)
Next
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
Dim sqlquery As String = "Update tblAppointments SET Present = #Present WHERE appID = #appID"
Dim sqlcommand As New OleDbCommand
For Each newrow As DataRow In dt.Rows
With sqlcommand
.CommandText = sqlquery
.Parameters.AddWithValue("#Present", newrow.Item(1))
.Parameters.AddWithValue("#appID", newrow.Item(0))
.ExecuteNonQuery()
End With
conn.Close()
Next
But have had no luck with doing so, as it crashes without an error.
Can anyone help?
I solved the problem myself, if any of you are having similar problems here is the solution
Dim dt As DataTable = New DataTable("SendTable")
Dim row As DataRow
dt.Columns.Add("appID", Type.GetType("System.Int32"))
dt.Columns.Add("Present", Type.GetType("System.Boolean"))
For i = 0 To Registersgridview.Rows.Count - 1
Dim appID As Integer = Registersgridview.Rows(i).Cells(0).Value
Dim present As Boolean = Registersgridview.Rows(i).Cells(4).Value
row = dt.Rows.Add
row.Item("appID") = appID
row.Item("Present") = present
Next
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
Dim sqlquery As String = "UPDATE tblAppointments SET Present = #Present WHERE appID = #appID"
Dim sqlcommand As New OleDbCommand
For Each newrow As DataRow In dt.Rows
With sqlcommand
.CommandText = sqlquery
.Parameters.AddWithValue("#Present", newrow.Item(1))
.Parameters.AddWithValue("#appID", newrow.Item(0))
.Connection = conn
.ExecuteNonQuery()
End With
Next
conn.Close()
Registersgridview.DataSource = Nothing
dt.Clear()
try this:
Dim dt As DataTable = New DataTable("SendTable")
Dim row As DataRow
dt.Columns.Add("appID", Type.GetType("System.Int32"))
dt.Columns.Add("Present", Type.GetType("System.Boolean"))
For i = 0 To Registersgridview.Rows.Count - 1
row = dt.Rows.Add
row.Item("appID") = Registersgridview.Rows(i).Cells(0)
row.Item("Present") = Registersgridview.Rows(i).Cells(5)
Next
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
Dim sqlquery As String = "Update tblAppointments SET Present = #Present WHERE appID = #appID"
Dim sqlcommand As New OleDbCommand
For Each newrow As DataRow In dt.Rows
With sqlcommand
.CommandText = sqlquery
.Parameters.AddWithValue("#Present", newrow.Item(5))
.Parameters.AddWithValue("#appID", newrow.Item(0))
.ExecuteNonQuery()
End With
conn.Close()
Next
At line 4 of my code, how or is it possible to have a condition in there?
For example:
Dim expr As String = "SELECT * FROM [Sheet1$] WHERE excelColumn1 <> NULL"
I have tried it, but it gives an Error: No value given for one or more required parameters.
Dim ExcelConnection As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\z.fontanilla\Documents\etl2.xlsx;Extended Properties=""Excel 12.0 Xml;HDR=Yes""")
ExcelConnection.Open()
Dim expr As String = "SELECT * FROM [Sheet1$]"
Dim objCmdSelect As OleDbCommand = New OleDbCommand(expr, ExcelConnection)
Dim objDR As OleDbDataReader
Dim SQLconn As New SqlConnection()
Dim ConnString As String = "Data Source=cyayay\sqlexpress;Initial Catalog=reportingDB;Integrated Security=True"
SQLconn.ConnectionString = ConnString
SQLconn.Open()
Using bulkCopy As SqlBulkCopy = New SqlBulkCopy(SQLconn)
bulkCopy.DestinationTableName = "tFalse"
Try
objDR = objCmdSelect.ExecuteReader
bulkCopy.BatchSize = 5000
bulkCopy.WriteToServer(objDR)
objDR.Close()
SQLconn.Close()
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Using
ExcelConnection.Close()
I am trying to fill a combobox with a SQL Result
I think my problem is handling the data in the datatable form.
Dim sql As String
Dim sqlquery As String
Dim ConnectionString As String
ConnectionString = "Data Source=(local);Initial Catalog=Control;Persist Security Info=True;User ID=user;Password=pass"
sqlquery = "Select dbName from Databases"
Using connection As SqlConnection = New SqlConnection(ConnectionString)
connection.Open()
Using conn As SqlCommand = New SqlCommand(sqlquery, conn)
Dim rs As SqlDataReader = comm.ExecuteReader
Dim dt As DataTable = New DataTable
dt.Load(cmboxDatabaseName)
End Using 'comm
End Using 'conn
When I run the program I just stare at a sad empty combobox.
Almost right, but you need to Load the datatable using the DataReader.
Then assing the DataTable to the DataSource of the Combo
Using connection As SqlConnection = New SqlConnection(ConnectionString)
connection.Open()
Using comm As SqlCommand = New SqlCommand(sqlquery, connection)
Dim rs As SqlDataReader = comm.ExecuteReader
Dim dt As DataTable = New DataTable
dt.Load(rs)
' as an example set the ValueMember and DisplayMember'
' to two columns of the returned table'
cmboxDatabaseName.ValueMember = "IDCustomer"
cmboxDatabaseName.DisplayMember = "Name"
cmboxDatabaseName.DataSource = dt
End Using 'comm
End Using 'conn
Also you could set the combobox ValueMember property to the name of the column that you will use as key for future processing and the DisplayMember property to the column name that you want to display as text to choose from for your user
you can also do it as
Dim Con = New SqlConnection(_ConnectionString)
Dim cmdAs New SqlCommand
Dim dr As New SqlDataReader
Try
If Con.State = ConnectionState.Closed Then
Con.Open()
cmd.Connection = Con
cmd.CommandText = "Select field1, field2 from table"
dr = cmd.ExecuteReader()
' Fill a combo box with the datareader
Do While dr.Read = True
ComboBoxName.Items.Add(dr.GetString(0))
ComboBoxName.Items.Add(dr.GetString(1))
Loop
Con.Close()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
Hope it works for you.
I am new to this and had this question. Can I use SQLDataReader instead of a Recordset. I want to achieve the following result in an SQLDataReader.
Dim dbConn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim sqlstr As String = "SELECT Name,Status FROM table1 WHERE id=" + item_id.Value.ToString
rs.Open(SQL, dbConn)
While Not rs.EOF
txtName.Text = rs.Fields.Item("Name").Value
ddlstatus.SelectedIndex = 1
rs.MoveNext()
End While
rs.Close()
rs = Nothing
dbConn.Close()
dbConn = Nothing
Can I replace recordset with SQLDataReader and if I can can you please show me the changes in code?
Its highly recommend that you use the using pattern:
Dim sConnection As String = "server=(local);uid=sa;pwd=PassWord;database=DatabaseName"
Using Con As New SqlConnection(sConnection)
Con.Open()
Using Com As New SqlCommand("Select * From tablename", Con)
Using RDR = Com.ExecuteReader()
If RDR.HasRows Then
Do While RDR.Read
txtName.Text = RDR.Item("Name").ToString()
Loop
End If
End Using
End Using
Con.Close()
End Using
You will have to swap out a few things, something similar to the following.
Here is an example, you will need to modify this to meet your goal, but this shows the difference.
I also recommend using a "Using" statement to manage the connection/reader. Also, a parameterized query.
Dim sConnection As String = "server=(local);uid=sa;pwd=PassWord;database=DatabaseName"
Dim objCommand As New SqlCommand
objCommand.CommandText = "Select * From tablename"
objCommand.Connection = New SqlConnection(sConnection)
objCommand.Connection.Open()
Dim objDataReader As SqlDataReader = objCommand.ExecuteReader()
If objDataReader.HasRows Then
Do While objDataReader.Read()
Console.WriteLine(" Your name is: " & Convert.ToString(objDataReader(0)))
Loop
Else
Console.WriteLine("No rows returned.")
End If
objDataReader.Close()
objCommand.Dispose()
Dim rdrDataReader As SqlClient.SqlDataReader
Dim cmdCommand As SqlClient.SqlCommand
Dim dtsData As New DataSet
Dim dtbTable As New DataTable
Dim i As Integer
Dim SQLStatement as String
msqlConnection.Open()
cmdCommand = New SqlClient.SqlCommand(SQLStatement, msqlConnection)
rdrDataReader = cmdCommand.ExecuteReader()
For i = 0 To (rdrDataReader.FieldCount - 1)
dtbTable.Columns.Add(rdrDataReader.GetName(i), rdrDataReader.GetFieldType(i))
Next
dtbTable.BeginLoadData()
Dim values(rdrDataReader.FieldCount - 1) As Object
While rdrDataReader.Read
rdrDataReader.GetValues(values)
dtbTable.LoadDataRow(values, True)
End While
dtbTable.EndLoadData()
dtsData.Tables.Add(dtbTable)
msqlConnection.Close()
Return dtsData