I've managed to get the following code...
con.ConnectionString = My.Settings.dbConnection
Dim sqlCmd As System.Data.OleDb.OleDbCommand = New System.Data.OleDb.OleDbCommand()
con.Open()
sqlCmd.Connection = con
Dim schemaTable As DataTable
schemaTable = con.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Views, Nothing)
To retrieve a list of Views in my Access database, but now I want to retrieve the results based on a selected View.
Is there a correct method in doing this, or do I take the SQL Statement from the DataTable returned for each row?
Suppose you have Query1 (View) in your Access database (Database1.accdb file). The following code will output each row of the query to the console (for demo purposes):
Dim con As OleDbConnection = New OleDbConnection()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Database1.accdb;Persist Security Info=False;"
Dim sqlCmd As OleDbCommand = New System.Data.OleDb.OleDbCommand()
sqlCmd.CommandType = CommandType.StoredProcedure
sqlCmd.CommandText = "Query1"
sqlCmd.Connection = con
con.Open()
Dim reader As OleDbDataReader
reader = sqlCmd.ExecuteReader()
If reader.HasRows Then
While reader.Read()
Console.WriteLine(reader("Column1")) 'output specific column
End While
End If
Console.ReadLine()
Hope this helps
Related
I am trying to improve performance of an application, I have a case where a common SPROC is being used but is it necessary to fill a DataTable just to set 2 variable values?
Is there anything more efficient?
Dim Conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("DB").ConnectionString)
Dim CmdUsers As SqlCommand = New SqlCommand("uspGetUsers", Conn)
CmdUsers.CommandType = CommandType.StoredProcedure
CmdUsers.Parameters.Add(New SqlParameter("#UserName", Session("UserID")))
Dim da As SqlDataAdapter = New SqlDataAdapter
Dim dtUserInfo As DataTable = New DataTable
da = New SqlDataAdapter(CmdUsers)
da.Fill(dtUserInfo)
isParent = dtUserInfo.Rows(0)("IsAdmin")
UserVal = dtUserInfo.Rows(0)("UserVal")
A SqlDataReader is the fastest way to read data from a query. Try the following:
Using conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("DB").ConnectionString)
conn.Open()
Using cmd As New SqlCommand("uspGetUsers", conn)
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters.AddWithValue("#UserName", Session("UserID"))
Using reader As SqlDataReader = cmd.ExecuteReader()
While reader.Read()
isParent = reader("IsAdmin")
UserVal = reader("UserVal")
End While
End Using
End Using
End Using
You may need to parse the data to the correct types.
Also, note the use of Using to automatically dispose of the connection, command and reader objects: http://msdn.microsoft.com/en-GB/library/htd05whh.aspx
This is what I've got so far :
Dim myCONN As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=w:\Baza.mdb")
Dim cmd1 = New OleDbCommand("SELECT ID FROM Baza WHERE NAZIV=#XXNAZIV")
cmd1.Parameters.AddWithValue("#XXNAZIV", TextBox2.Text)
cmd1.Connection = myCONN
myCONN.Open()
Dim result = cmd1.ExecuteReader()
While (result.Read())
Dim rowx As Integer = GetTextOrEmpty(result("ID"))
End While
I've found the row (rowx) in which I would like to change values in 20 corresponding columns (namesID : NAZIV, SIFRA,...). Data is already presented in textboxes (textbox1...), but I don't know how to finish this code with UPDATE and how to insert changed values back to Access.
Dim cmdText As String = "UPDATE Baza SET NAZIV=#XXNAZIV Where ID=SomeId"
Using con = new OleDbConnection("PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source = h:\Baza.mdb")
Using cmd = new OleDbCommand(cmdText, con)
con.Open()
cmd.Parameters.AddWithValue("#XXNAZIV",TextBox2.Text)
cmd.ExecuteNonQuery()
End Using
End Using
This should help you to solve your problem, of course you will have to pass ID parameter to query also.
Reference
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 have this code that populates a datagridview with data from ms access:
Dim con As New OleDbConnection
Dim ds As New DataSet
Dim da As OleDb.OleDbDataAdapter
Dim Sql As String
Sql = "SELECT * FROM myTable WHERE case_no=?"
Try
con.ConnectionString = "PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source=Sample.accdb;Persist Security Info=True;Jet OLEDB:Database Password=dbadmin2010"
con.Open()
Dim cmd As OleDbCommand = New OleDbCommand(Sql, con)
da.SelectCommand = cmd
cmd.Parameters.AddWithValue("case_no", case_no)
Dim ds As DataSet = New DataSet
da.Fill(ds, "Case Info")
DataGridView1.DataSource = ds.Tables("Case Info")
Catch ex As Exception
MsgBox(ex.Message)
End Try
Now I had just finished creating a query from design view within MS Access itself, is there a way to call that query and retrieve the results to my datagridview?
Just use the query name and set the command type, for example, in addition to what you already have, you can use the following notes:
Try
con.ConnectionString = enter_connection_string_here
con.Open()
cmd.Connection = con
cmd.CommandType = CommandType.StoredProcedure
cmd.CommandText = "NameOfQuery"
da.SelectCommand = cmd
cmd.Parameters.AddWithValue("case_no", case_no)
da.Fill(ds, "Case Info")
I'm currently working on an ms access database in vb.net.
And I need a code that can determine which data I am updating in the database. Because when I try to update the data, the previous data is being cloned and it will generate two data(the updated and the previous data), and the program will also generate a random id number for the updated data, which is not good.
Here is my code for the update button:
'update
Dim cb As New OleDb.OleDbCommandBuilder(da)
ds.Tables("GH").Rows(INC).Item(1) = TextBox13.Text
ds.Tables("GH").Rows(INC).Item(2) = TextBox14.Text
ds.Tables("GH").Rows(INC).Item(3) = TextBox15.Text
da.Update(ds, "GH")
MsgBox("Data updated")
My code for form load:
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=F:\ACCESS DATABASE\search.mdb"
con.Open()
sql = "SELECT * FROM GH"
da = New OleDb.OleDbDataAdapter(sql, con)
da.Fill(ds, "GH")
con.Close()
I'm using system.data.oledb namespace
Here are my declarations:
Dim cmd As OleDbCommand
Dim cn As OleDbConnection
Dim dr As OleDbDataReader
Dim ds As New DataSet
Dim con As New OleDb.OleDbConnection
Dim da As OleDb.OleDbDataAdapter
Your question is not clear to me at all, but if you want to find the last ID of an insert, you would usually check the results of "SELECT ##IDENTITY" immediately after the record is inserted.