Really sorry if this has been asked 10000 times but i couldn't find anything about it.
I'm making backup copies of database tables from a dev site to a live site and i am using this code to do so but i have another 10 tables to copy over and I'm sure there must be an easier way that this?
Dim AccessConn As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.MapPath("../../_db/db.mdb") & "")
AccessConn.Open()
Dim AccessCommand As New System.Data.OleDb.OleDbCommand("DELETE * FROM news", AccessConn)
AccessCommand.ExecuteNonQuery()
Dim AccessCommand2 As New System.Data.OleDb.OleDbCommand("INSERT INTO news SELECT * FROM news_dev WHERE isapproved", AccessConn)
AccessCommand2.ExecuteNonQuery()
Response.Write("News Updated")
Response.Write("<br />")
Dim AccessCommand3 As New System.Data.OleDb.OleDbCommand("DELETE * FROM pages", AccessConn)
AccessCommand3.ExecuteNonQuery()
Dim AccessCommand4 As New System.Data.OleDb.OleDbCommand("INSERT INTO pages SELECT * FROM pages_dev WHERE isapproved", AccessConn)
AccessCommand4.ExecuteNonQuery()
Response.Write("Pages Updated")
Response.Write("<br />")
AccessConn.Close()
Related
I am trying to get multiple rows into a table hence my attempt to get the row number and put it into a for loop, the countC is exactly the same number of rows as the select statement, so the issue is not there
I'm using an oledb connection as my code is in vb asp.net but my database is in ms access 2003
For c As Integer = 1 To countC
Dim cmdstring As String
cmdstring = " INSERT INTO [KN - ProductionMachineAllocation] (BatchNo, ComponentID)
SELECT POH.BatchNo, SSCDD.ComponentID
FROM (
SELECT ROW_NUMBER() OVER (ORDER BY BatchNo ASC) AS rownumber
([KN - ProductionOrderHeader] AS POH
INNER JOIN [FG - End Product Codes] AS EPC
ON POH.ProductID = EPC.ProductID)
INNER JOIN ([KN - ProductionOrderDetails] AS POD
INNER JOIN [FG - Style Size Comp Def Details] AS SSCDD
ON POD.SizeID = SSCDD.SizeID)
ON (POH.BatchNo = POD.BatchNo)
AND (EPC.StyleID = SSCDD.StyleID)
WHERE POH.BatchNo = '" & BatchNo & "'
) AS temptablename
WHERE rownumber IN (" & c & ");"
Dim con As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Shantara Production IT.mdb")
Dim cmd As New OleDbCommand(cmdstring)
cmd.CommandType = CommandType.Text
cmd.Connection = con
cmd.Connection.Open()
cmd.ExecuteNonQuery()
cmd.Connection.Close()
Next
I found out that ms access doesn't support ROW_NUMBER() so I need to find another going through each row since ms access doesn't support multi row insert by insert into select statement such as mine, any suggestions around my problem?
Most databases are able to do all this work much more efficiently entirely in the database. Certainly in SQL Server I could get entire thing down to a single query. Access is a little different, since vbscript is its procedural language, rather than something more like t-sql. There's still probably a way to do it, but since what you have works, we can at least focus on making that better.
GridViews are visual constructs that will use up extra memory and resources. If Access won't do a real INSERT/SELECT, you can at least read direct from the previous result set into your insert. You can also improve on this significantly by using parameters and re-using a single open connection for all the inserts:
Dim cnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Shantara Production IT.mdb"
Dim SQLDown As String = _
"SELECT DISTINCT POH.BatchNo, SSCDD.ComponentID
FROM ([KN - ProductionOrderHeader] AS POH
INNER Join [FG - End Product Codes] AS EPC
On POH.ProductID = EPC.ProductID)
INNER Join([KN - ProductionOrderDetails] AS POD
INNER Join [FG - Style Size Comp Def Details] AS SSCDD
On POD.SizeID = SSCDD.SizeID)
On (POH.BatchNo = POD.BatchNo)
And (EPC.StyleID = SSCDD.StyleID)
WHERE POH.BatchNo = ? "
Dim SQLUp As String = _
" INSERT INTO [KN - ProductionMachineAllocation]
(BatchNo, ComponentID)
VALUES( ?, ? )"
Dim dt As New DataTable
Using con As New OleDbConnection(cnString), _
cmd As New OleDbCommand(SQLDown, con)
'Guessing at parameter type/length here.
'Use the actual column type and size from your DB
cmd.Parameters.Add("#BatchNo", OleDbType.VarWChar, 10).Value = BatchNo
con.Open()
dt.Load(cmd.ExecuteReader())
End Using
Using con As New OleDbConnection(cnString), _
cmd As New OleDbCommand(SqlUp, con)
'Guessing at parameter types/lengths again
cmd.Parameters.Add("#BatchNo", OleDbType.VarWChar, 10)
cmd.Parameters.Add("#ComponentID", OleDbType.Integer)
'Connection is managed *outside of the loop*. Only one object created, only one negotiation with DB
con.Open()
For Each row As DataRow In dt.Rows
cmd.Parameters(0).Value = row(0)
cmd.Parameters(1).Value = row(1)
cmd.ExecuteNonQuery()
Next
End Using
Normally, with any ADO.Net provider you do not re-use your connection or command objects. You want a new connection object for every query sent to the DB to allow connection pooling to work correctly. Using the connection in a tight loop like this for the same query is one of the few exceptions.
I might be able to improve further by sticking with the active DataReader, rather than first loading it into a DataTable. That would allow us to avoid loading the entire result set into memory. You would only ever need one record in memory at a time. Certainly this would work for Sql Server. However, Access was designed mainly as a single-user database. It doesn't really like multiple active connections at once, and I'm not sure how it would respond.
It would also be nice to be able to do all of this work in a transactional way, where there's never any risk of it failing part way through the loop and getting stuck with half the updates. Sql Server would handle this via a single INSERT/SELECT query or with an explicit transaction. But, again, this isn't the kind of the Access is designed for. It probably does have a way to do this, but I'm not familiar with it.
OK SO I finally found a way around it, it's a bit of a long process but basically I loaded the SELECT statement(with multiple rows) into a gridview table and the used a for loop to insert it into my insert into statement. bellow is my code:
Displaying into a table
Dim Adapter As New OleDbDataAdapter
Dim Data As New DataTable
Dim SQL As String
Dim con As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Shantara Production IT.mdb")
Dim cmd As New OleDbCommand()
grdvmachincomp.Visible = false
SQL = "SELECT DISTINCT POH.BatchNo, SSCDD.ComponentID
FROM ([KN - ProductionOrderHeader] AS POH
INNER Join [FG - End Product Codes] AS EPC
On POH.ProductID = EPC.ProductID)
INNER Join([KN - ProductionOrderDetails] AS POD
INNER Join [FG - Style Size Comp Def Details] AS SSCDD
On POD.SizeID = SSCDD.SizeID)
On (POH.BatchNo = POD.BatchNo)
And (EPC.StyleID = SSCDD.StyleID)
WHERE POH.BatchNo = '" & BatchNo & "'"
con.Open()
cmd.Connection = con
cmd.CommandText = SQL
Adapter.SelectCommand = cmd
Adapter.Fill(Data)
grdvmachincomp.DataSource = Data
grdvmachincomp.DataBind()
cmd.Connection.Close()
Insert into through for loop
For c As Integer = 0 To grdvmachincomp.Rows.Count - 1
Dim cmdstring As String
cmdstring = " INSERT INTO [KN - ProductionMachineAllocation] (BatchNo, ComponentID) VALUES('" & grdvmachincomp.Rows(c).Cells(0).Text & "', " & grdvmachincomp.Rows(c).Cells(1).Text & ");"
Dim con As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Shantara Production IT.mdb")
Dim cmd As New OleDbCommand(cmdstring)
cmd.CommandType = CommandType.Text
cmd.Connection = con
cmd.Connection.Open()
cmd.ExecuteNonQuery()
cmd.Connection.Close()
Next
Inherited a SQL database with an MS Access .adp front end which is being converted to ASP.net VB. Using a conversion tool which has done a good job on most of it after debugging. It however could not convert DLookup functions used in combo boxes as it is not supported. Being relativley new to .net am unclear how to convert the DLookup function to a SQL statement. The table name: dbo.Contact
The main form name: Contact_Edit
The sub form name: Contact_Edit_Sub
There are a number of combo boxes with many Dlookup functions. Once I have one I can rework the balance. Any help with converting the statement is appreciated.
The current code is listed below:
*If Not IsDBNull(Me.Contact_Edit.Contact_Edit_Sub.Intake_Worker_Code) Then
Intake_Worker_Code_Desc.Text = DLookup("[Name]", "Staff", "Code ='" & Intake_Worker_Code.SelectedValue & "'")
Else
Intake_Worker_Code_Desc.Text = ""
End If*
Try this, where [Name] is the field and Staff is the table
SELECT [Name] FROM Staff WHERE Code = '" & Intake_Worker_Code.SelectedValue & "';
Here you can read more about what DLookup does:
http://www.techonthenet.com/access/functions/domain/dlookup.php
https://support.office.com/en-us/article/DLookup-Function-8896cb03-e31f-45d1-86db-bed10dca5937
Update based on comment
VB.Net SQL code sample
If Not IsDBNull(Me.Intake_Worker_Code) Then
Dim conn_str As String = ConfigurationManager.ConnectionStrings("YourConnectionString").ConnectionString
Dim myconn As New SqlConnection(conn_str)
Dim sc As New SqlCommand()
sc.CommandText = "Select [Name] FROM [Staff] WHERE (Code = '") & (Intake_Worker_Code.SelectedValue & "')"
sc.Connection = myconn
myconn.Open()
Intake_Worker_Code_Desc.Text = sc.ExecuteScalar().ToString()
myconn.Close()
Else
Intake_Worker_Code_Desc.Text = ""
End If
I'm currently creating a vb.net application and i found a tutorial to create a log in script, the code of which is as follows:
Private Sub btnLogin_Click_1(sender As Object, e As EventArgs) Handles btnLogin.Click
Dim con As New SqlClient.SqlConnection(MyConnection.MyConnectionString)
con.Open()
Dim dr As SqlClient.SqlDataReader
Dim cmd As New SqlClient.SqlCommand("select * from [customer_login] where username='" + tbUsename.Text + "' and password='" + tbPassword.Text + "'", con)
dr = cmd.ExecuteReader
If dr.Read Then
Dim
MsgBox("you are logged on as " + tbUsename.Text)
TabControl1.SelectedTab = tabDetails
End If
End Sub
Though i'll be the first to admit i still don't have a full understanding of how this code works... But anyway i'd now like use this logged in state to pull relevant data (such as the users name and address etc.) from my sql server database to autocomplete textboxes in the next window. I'm sure this is possible, and i'm sure it's pretty simple but i cant seem to figure it out. Can anyone explain this to me or point me to a suitable tutorial. Thanks in advance.
why you are not to get select again, on dr.read and put into a datatable so you can put your temp data what you want to other form.
I am Newbie to NET I have been fighting with this issue from 3 days unable to solve ![1
The Data base names are Tbl_Employees,Tbl_Project
i have to fetch Username and Project two fields from the above two tables using project_id as primary key between them and load the data in grid view .Inputs needed for Loading the Grid
I'm am not sure what exactly you require but it seems like the basics of grid view. Please use this excellent reference to assist your problem. http://technico.qnownow.com/tag/gridview/
Because the tag was changed from c# to vb.net I'll leave my previous answer. Please try the following. I've added a SqlCommand
The VB.NET code
Dim da As New SqlDataAdapter
Dim DS As New DataSet
Dim mySelectQuery As String = "SELECT dbo.Tbl_Project.Project, dbo.Tbl_Employees.User_Name FROM dbo.Tbl_Employees INNER JOIN dbo.Tbl_Project ON dbo.Tbl_Employees.Project_ID = dbo.Tbl_Project.Project_ID"
Dim ConnString As String = "Data Source=yourSQLServer; Initial Catalog=yourDB; User Id=yourUserName; Password=yourPwd;" ''Change to you database/server specifics
Dim myConnection As New SqlConnection(ConnString)
Dim myCommand As New SqlCommand(mySelectQuery, myConnection)
myConnection.Open()
da.SelectCommand = myCommand
da.Fill(DS,"Project")
If Not DS.Tables(0).Rows.Count > 0 Then
MessageBox.Show("There were no results found. ", "No Results Found", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
Else
gridview3.DataSource = Ds
gridview3.DataBind()
myConnection.Close()
End If
References to connection strings
http://www.sql-server-helper.com/sql-server-2008/sqlconnection-connection-string.aspx
I am currently working on an asp.net web page with a GridView displaying a table from a database. This GridView has 4 DropDownLists that will be used to filter the data shown on the GridView. When the page loads 4 Sub routines are run, each one connecting to the database with a select statement to fill the DropDownList with relevant filter headings.
Initially, I had one connection with a loop that populated all of the drop downs but these contained duplicates. I then split the filling of each DDL so that the select statements could contain DISTINCT.
I would like (and am sure there is a way here) to be able to populate all of the DDLs with data from one connection.
Code for one connection:
Protected Sub FillDepDDL()
Dim conn As New SqlConnection()
conn.ConnectionString = WebConfigurationManager.ConnectionStrings("TestDBConnectionString").ConnectionString
Dim connection As New SqlConnection(conn.ConnectionString)
connection.Open()
Const FillAllQS As String = "SELECT DISTINCT [Department] FROM [Employees]"
Dim command As New SqlCommand(FillAllQS, connection)
Dim reader As SqlDataReader = command.ExecuteReader()
Dim sel As New ListItem
sel.Text = "Please Select"
sel.Value = "*"
DDLDepartment.Items.Add(sel)
While reader.Read
Dim Deplist As New ListItem()
Deplist.Value = reader("Department")
Deplist.Text = reader("Department")
DDLDepartment.Items.Add(Deplist)
End While
reader.Close()
conn.Close()
End Sub
The other 3 column names: FirstName > DDLFN, LastName > DDLLN, Wage > DDLWag.
This is only a test DB and the princibles learned here will be applied to a larger live project.
I'm sure some guru will be able to work this out easily but I just can't get my head round it even after hours of searching.
Thanks in advance.
I'm adding this in as answer because I cannot format it in a comment, but this doesn't answer the original question of how to write the sql to return all three distinct result sets. Instead, it answers how to rewrite the code you have above so that connections are properly disposed of in case of an exception.
Protected Sub FillDepDDL()
Dim Deplist As ListItem
Dim sel As New ListItem
sel.Text = "Please Select"
sel.Value = "*"
DDLDepartment.Items.Add(sel)
Using conn As New SqlConnection(WebConfigurationManager.ConnecitonString("TestDBConnectionString").ConnectionString)
Using cmd As New SqlCommand("SELECT DISTINCT [Department] FROM [Employees]", conn)
conn.Open()
Using reader = cmd.ExecuteReader()
While reader.Read
Deplist = New ListItem()
Deplist.Value = reader("Department")
Deplist.Text = reader("Department")
DDLDepartment.Items.Add(Deplist)
End While
End Using
End Using
End Using
End Sub
I don't see any reason for you to try to return all three results in a single query. That will just make your code unnecessarily complicated just to save a millisecond or two. Connection pooling handles the creation of connections on the database server for you, so opening a new connection in your code is very fast.