I have problem with data that needs to be seen on datagridview. Bellow is my code:
Public Class Form3
Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim CONNECT_STRING As String = (...)
Dim cnn As New OleDbConnection(CONNECT_STRING)
cnn.Open()
MsgBox(status_narocila.value)
Dim sql As String = "SELECT artikel.st_artikla, artikel.naziv_artikla, narocilo.kolicina, narocilo.barva_tiska, narocilo.izvedba, narocilo.opombe, narocilo.datum_narocila, narocilo.rok_izdelave, narocilo.status, narocilo.ID FROM (narocilo INNER JOIN artikel ON narocilo.id_artkla = artikel.ID) WHERE(narocilo.ID = '" & status_narocila.value & "')"
Dim cmd As New OleDbCommand(sql, cnn)
Dim da As New OleDbDataAdapter(cmd)
Dim ds As New DataSet
da.Fill(ds, "artikel")
cnn.Close()
DataGridView1.DataSource = ds.Tables("artikel")
End Sub
End Class
Value status.narocila.value is integer, I've tested it and getting right value from it. The code is working fine without WHERE clause.
= '" & status_narocila.value & "')"
should be
= " & status_narocila.value & ")"
no ' on numeric data types.
If narocilo.ID is also an integer, then the problem is you're using text qualifers on an integer field.
Try changing your WHERE clause to:
WHERE(narocilo.ID = " & status_narocila.value & ")"
Related
Imports System.Data.OleDb
Public Class Form1
Dim conn As OleDbConnection
Dim cmd As OleDbCommand
Dim da As OleDbDataAdapter
Dim strSQL As String
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles btnsearch.Click
Dim fieldselect As String = ""
Select Case ComboBox1.Text
Case "startYear"
fieldselect = "startYear"
Case "genres"
fieldselect = "genres"
Case "Rating"
fieldselect = "Rating"
End Select
conn = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=Movies.accdb; Persist Security Info=False;")
strSQL = "SELECT startYear, genres, averageRating FROM (basic.tconst Inner JOIN Rating.tconst on basic.tconst=Rating.tconst)" & fieldselect & "'" & TextBox1.Text & "%'"
conn.Open()
da = New OleDbDataAdapter(strSQL, conn)
Dim ds As New DataSet("Movies")
da.Fill(ds, "Movies")
DataGridView1.DataSource = ds.Tables("Movies")
conn.Close()
End Sub
Keep you data objects local so you can control there closing and disposing. Using...End Using blocks do this for you even it there is an error.
Are all your fields in the Select Case the same datatype? If not you will have to adjust the code. If you need help, tell me the datatypes so I can fix the code.
Always use parameters to avoid sql injection. A text box can hold a Drop Table command. Parameters are treated as values not executable code.
If you need to update later in the code, you will need to have a primary key available in your Select.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Since your field name exactly matches the combo text the Case statement is not necessary
Dim fieldselect As String = ComboBox1.Text
Dim dt As New DataTable
Using conn = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=Movies.accdb; Persist Security Info=False;")
Dim strSQL = "SELECT startYear, genres, averageRating FROM basic.tconst Inner JOIN Rating.tconst on basic.tconst=Rating.tconst Where " & fieldselect & " = #FieldValue;"
Using cmd As New OleDbCommand(strSQL, conn)
cmd.Parameters.Add("#FieldValue", OleDbType.VarChar).Value = TextBox1.Text
conn.Open()
dt.Load(cmd.ExecuteReader)
End Using
End Using
DataGridView1.DataSource = dt
End Sub
i wanted to use combo box as the filter for my program, i need to filter data from 2 different table. rating has it own table and basic is different table. both of the field mention above does not have any connection.
It's a bit had to help without context but I gave it a try :
I would replace
strSQL = "SELECT startYear, genres, averageRating FROM (basic.tconst Inner JOIN Rating.tconst on basic.tconst=Rating.tconst)" & fieldselect & "'" & TextBox1.Text & "%'"
With
"SELECT startYear, genres, averageRating " &
"FROM basic.tconst " &
"INNER JOIN Rating.tconst on basic.tconst=Rating.tconst " & fieldselect & "'" & TextBox1.Text & "%'"
To get better help, could you explain how tables Rating and basic works and what fieldselect is ?
I have the following code and through debugging the problem begins at the While loop. I am trying to retrieve information from 2 tables and insert it into the table created. The information is not being inserted into the table and I am getting blank rows.
Imports System.Data.OleDb
Public Class RouteToCruise
Private Sub RouteToCruise_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Sub Route_Btn_Click(sender As Object, e As EventArgs) Handles Route_Btn.Click
Dim row As String
Dim connectString As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=M:\ICT-Group-Project\DeepBlueProject\DeepBlueProject\DeepBlueTables.mdb"
Dim cn As OleDbConnection = New OleDbConnection(connectString)
cn.Open()
Dim CruiseQuery As String = "SELECT CruiseID, RouteID FROM Cruise WHERE CruiseID =?"
Dim RouteQuery As String = "SELECT RouteName FROM Route WHERE RouteID =?"
Dim cmd As OleDbCommand = New OleDbCommand(CruiseQuery, cn)
Dim cmd2 As OleDbCommand = New OleDbCommand(RouteQuery, cn)
cmd.Parameters.AddWithValue("?", Route_Txt.Text)
Dim reader As OleDbDataReader
reader = cmd.ExecuteReader
'RCTable.Width = Unit.Percentage(90.0)
RCTable.ColumnCount = 2
RCTable.Rows.Add()
RCTable.Columns(0).Name = "CruiseID"
RCTable.Columns(1).Name = "Route"
While reader.Read()
Dim rID As String = reader("RouteID").ToString()
cmd2.Parameters.AddWithValue("?", rID)
Dim reader2 As OleDbDataReader = cmd2.ExecuteReader()
'MsgBox(reader.GetValue(0) & "," & reader.GetValue(1))
row = reader("CruiseID") & "," & reader2("RouteName")
RCTable.Rows.Add(row)
cmd.ExecuteNonQuery()
reader2.Close()
End While
reader.Close()
cn.Close()
End Sub
End Class
If I understand your tables structure well then you could just run a single query extracting data from the two table and joining them in a new table returned by the query
Dim sql = "SELECT c.CruiseID c.CruiseID & ',' & r.RouteName as Route " & _
"FROM Cruise c INNER JOIN Route r ON c.RouteID = c.RouteID " & _
" WHERE c.CruiseID = #cruiseID"
Dim cmd As OleDbCommand = New OleDbCommand(sql, cn)
cmd.Parameters.Add("#cruiseID", OleDbType.Int).Value = Convert.ToInt32(Route_Txt.Text)
Dim RCTable = new DataTable()
Dim reader = cmd.ExecuteReader()
reader.Load(RCTable)
At this point the RCTable is filled with the data coming from the two tables and selected using the Route_Txt textbox converted to an integer. If the CruiseID field is not a numeric field then you should create the parameter as of type OleDbType.VarWChar and remove the conversion to integer
Try simplifying your query.
Dim CruiseRouteQuery As String = "SELECT C.CruiseID, C.RoutID, R.Routename FROM Cruise C LEFT JOIN Route R ON C.RouteID = R.RoutID WHERE CruiseID =?"
Also, please let us know what errors you are getting.
I'm writing a calorie counter tool for my girlfriend...
But I've run in to an issue I really cant figure out...
I have place in my script where I would wanna take some information out from my db...
The specific place in the script thats teasing, is the one that will take out data from a row called "antal" from a table called "items".
One place in my script, I call "navn" from items, and it works perfect...
This other place, it gives me the error that there isn't any data in the row!
My code looks so far like this:
Imports System.Data.OleDb
Private Sub ins_kat_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ins_kat.SelectedIndexChanged
Dim Con = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\Privat\MCC\mccdb.mdb")
Con.Open()
Dim command As OleDbCommand = New OleDbCommand("SELECT * FROM items WHERE kat = '" & ins_kat.Text & "' ORDER BY id DESC", Con)
Dim read As OleDbDataReader = command.ExecuteReader()
ins_mad.Items.Clear()
While read.Read()
ins_mad.Items.Add(read.Item("navn")) '<---- This place works!!!
End While
Con.Close()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim ialt_c_counter As String
Dim ialt_c_counter_conv As Decimal
Dim ialt_c_counter_conv2 As Decimal
Dim ialt_counter As String
Dim ialt_final As Decimal
Dim Con = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\Privat\MCC\mccdb.mdb")
Con.Open()
Dim command1 As OleDbCommand = New OleDbCommand("SELECT * FROM food WHERE dag = '" & stat_dag.Text & "' AND maaned = '" & stat_maaned1.Text & "' AND aar = '" & stat_aar1.Text & "'", Con)
Dim read1 As OleDbDataReader = command1.ExecuteReader()
While read1.Read()
ialt_c_counter = read1.Item("antal")
ialt_c_counter_conv = System.Convert.ToDecimal(ialt_c_counter)
Dim commandX As OleDbCommand = New OleDbCommand("SELECT * FROM items", Con)
Dim reader As OleDbDataReader = commandX.ExecuteReader()
ialt_counter = reader.Item("antal") '<--- THIS ONE is giving me the error!!
ialt_c_counter_conv2 = System.Convert.ToDecimal(ialt_counter)
ialt_final = (ialt_c_counter_conv / 100 * ialt_c_counter_conv2) + ialt_final
End While
Con.Close()
MsgBox(ialt_final)
End Sub
End Class
By now, I want a MsgBox telling me the result of my algorithm, but I don't even get that far cause of the error message...
I guess the error you see is
InvalidOperationException: Invalid attempt to read when no data is present.
You never call Read() on the OleDbDataReader called reader.
Note how you use a While loop to call Read() for read and read1, but not reader (bad variable names, btw).
I'm a student currently doing my programming coursework. I am trying to get the MemberID from the Access database using a button in my DataGridView, but I end up with an error Data type mismatch in criteria expression when I select the member I wish to view. This is my code below:
Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
Dim Member As String
Dim ds As New DataSet
Dim da As OleDb.OleDbDataAdapter
da = New OleDb.OleDbDataAdapter(Query, Conn)
Connect = "PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source = \\DRS-SR-002\RMShared Documents\Computer Programming\Programs\year13\Kevin\Project\Database tables\DBTables.accdb"
Conn = New OleDb.OleDbConnection(Connect)
If e.ColumnIndex <> 4 Then
Exit Sub
End If
Dim MemberSelectedID As String = DataGridView1.Rows(e.RowIndex).Cells(0).Value
GroupBox1.Show()
Query = "SELECT MemberID FROM tblMember WHERE [MemberID] = """ & MemberSelectedID & """"
Conn.Open()
da = New OleDb.OleDbDataAdapter(Query, Conn)
da.Fill(ds, "Selected Member")
Conn.Close()
Member = ds.Tables("Selected Member").Rows(0).Item(0)
TextBox1.Text = Query
End Sub
Your Query is wrong.
It should be like this.
Query = "SELECT MemberID FROM tblMember WHERE [MemberID] = " & MemberSelectedID
OR
Query = "SELECT MemberID FROM tblMember WHERE [MemberID] = '" & MemberSelectedID & "'"
MemberID field is Integer so no need to specify it as string.
In SQL Server single quote ' is used to specify string not double quote ".
You are getting the MemberSelectedID from the DataGridView as String and then using it to query the database, on which I assume that it is defined as Numeric. That's the reason of the data type mismatch error
Try:
Dim MemberSelectedID As Integer = DataGridView1.Rows(e.RowIndex).Cells(0).Value
And
Query = "SELECT MemberID FROM tblMember WHERE MemberID = " & MemberSelectedID
I am using MS Access Database. Now I have to update a particular cell value. Here is my code:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim str As String
Dim Presc As New System.Text.StringBuilder
Dim prs As String(), j As Integer
prs = Split(txtPrescription.Text, vbCrLf)
For j = 0 To prs.Length - 1
Presc.Append(prs(j))
Presc.Append(",")
Next
Try
str = Trim(lsvCase.SelectedItems(0).Text)
'MessageBox.Show(str)
Dim con As System.Data.OleDb.OleDbConnection
Dim ds As New DataSet
Dim rea As System.Data.OleDb.OleDbDataReader
con = New OleDb.OleDbConnection
Dim da As New System.Data.OleDb.OleDbDataAdapter
con.ConnectionString = "Provider = Microsoft.ACE.OLEDB.12.0; Data Source= F:\Sowmya Laptop Backups\sowdb1.accdb;"
con.Open()
Dim cmd As OleDb.OleDbCommand = con.CreateCommand
cmd.CommandText = "UPDATE Casehistory set Prescription =' " & Presc.ToString() & "'"
rea = cmd.ExecuteReader
cmd.ExecuteNonQuery()
da.FillSchema(ds, SchemaType.Mapped)
da.Update(ds, "Casehistory")
con.Close()
Catch ex As Exception
Finally
End Try
End Sub
This code updates all the cells in that column. I want to update only the particular cell having Case_ID = str
Where I have to add the WHERE clause (WHERE Case_ID = " & str & "
I would use command parameters, neater and prevents the SQL injection issue. Something like:
cmd.CommandText = "UPDATE Casehistory set Prescription =#Presc WHERE Case_ID = #CaseID"
cmd.Parameters.AddWithValue("#Presc", Presc.ToString())
cmd.Parameters.AddWithValue("#CaseID",str)
As an aside, having all this code in the button click event is less than ideal. You might want to investigate structuring your app in a more maintainable way - perhaps with a Data Layer for example.
The Where clause should be appended to the end of the OleDbCommmand.CommandText, where you define the Update statement.