I was wondering how I could change the code below, to allow me to search for the most recent record. I am creating a Hotel Booking System and want to use the most recent price in the database but at the moment, it is just searching using the labels which I don't want.
Dim str1 As String
Dim dbpassword As String = "123"
Dim connString As String = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source= E:\Computing\Hotel Booking System\Database\Hotel Booking System.accdb ;Jet OLEDB:Database Password =" & dbpassword & ";"
Dim MyConn As OleDbConnection
Dim dr As OleDbDataReader
Private Sub Information_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim PriceFound As String = False
MyConn = New OleDbConnection
MyConn.ConnectionString = connString
MyConn.Open()
str1 = ("SELECT * FROM [Prices] WHERE [Adult] = '" & LblPriceAdult.Text & "' AND [Child] = '" & LblPriceChild.Text & "'")
Dim cmd1 As OleDbCommand = New OleDbCommand(str1, MyConn)
dr = cmd1.ExecuteReader
While dr.Read()
PriceFound = True
DateDisplay = dr("ID").ToString
AdultPrice = dr("Adult").ToString
ChildPrice = dr("Child").ToString
SingleRoom = dr("Single").ToString
DoubleRoom = dr("Double").ToString
FamilyRoom = dr("Family").ToString
If PriceFound = True Then
LblPriceAdult.Text = AdultPrice
LblPriceChild.Text = ChildPrice
LblPriceDoubleRoom.Text = DoubleRoom
LblPriceFamilyRoom.Text = FamilyRoom
LblPriceSingleRoom.Text = SingleRoom
End If
End While
MyConn.Close()
End Sub
Based on your previous comments, you need to rewrite your SQL to trap the most recent record.
Try something like this:
SELECT MAX(ID) FROM [Prices] ORDER BY ID DESC
I tried the answer above. However for the code above, it wouldn't search for the most recent so I changed DESC to ASC
Related
I have a list of student names in a listBox,(studentList)I click on a name in the box and get all the students details up ie name, course, subject etc.The code then gets the details from the database(in my case it's access) then displays it in a datagridview.
The code works fine if I just select one item from one(or all)List Boxes.My question is, can I select more than one item per LitsBox.I know I can use SelectedMode property to allow the highlighting but that wont draw the required data from the database.Here is the code I am using vb.10
`Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim con As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
Dim ds As New DataSet
Dim tables As DataTableCollection = ds.Tables
Dim source1 As New BindingSource()
Dim da As New OleDb.OleDbDataAdapter
dbProvider = "PROVIDER=Microsoft.ACE.OLEDB.12.0;"
dbSource = "Data Source = C:\Documents and Settings\Desktop \studentmarks.accdb"
con.ConnectionString = dbProvider & dbSource
con.Open()
Dim isFirstColumn As Boolean = True
Dim student As String = ""
Dim course As String = ""
Dim grade As String = ""
Dim x As String = studentList.Text
Dim y As String = courseList.Text
Dim z As String = gradeList.Text
Dim defaultSQL As String = "SELECT * FROM studentfile "
If studentList.SelectedIndex > -1 Then
If isFirstColumn Then
student = "WHERE student = '" & x & "' "
Else
student = "AND student = '" & x & "' "
End If
isFirstColumn = False
End If
If courseList.SelectedIndex > -1 Then
If isFirstColumn Then
course = "WHERE course = '" & y & "' "
Else
course = "AND course = '" & y & "' "
End If
isFirstColumn = False
End If
If gradeList.SelectedIndex > -1 Then
If isFirstColumn Then
grade = "WHERE grade = '" & z & "' "
Else
grade = "AND grade = '" & z & "' "
End If
isFirstColumn = False
End If
Dim sql As String = defaultSQL & student & course & grade
da = New OleDb.OleDbDataAdapter(sql, con)
da.Fill(ds, "topclass")
Dim view1 As New DataView(tables(0))
source1.DataSource = view1
DataGridView1.DataSource = view1
DataGridView1.Refresh()
DataGridView1.DataSource = view1
DataGridView1.Refresh()
Dim cnt As Integer
cnt = DataGridView1.Rows.Count
TextBox1.Text = cnt - 1
Dim dayclass As String = TextBox1.Text
TextBox8.Text = dayclass
con.Close()
End Sub`
many thanks
grey
Using the .SelectedItems (and a lot of jiggery with the where clause.... you should be able to use this to EITHER have multi-select of single select accross all three listboxes as well as not selecting anything from any of them too...
The only question I would have would be whether you want all the 'AND's as this would mean if you selected two students, you wouldnt get any results... as no two students are the same right? Unless you selected two 'Dave's in which it would return both. For example!
Might suggest changing some for 'OR's or look at what the end result might be? Either way comment and let us know if need any further help
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim con As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
Dim ds As New DataSet
Dim tables As DataTableCollection = ds.Tables
Dim source1 As New BindingSource()
Dim da As New OleDb.OleDbDataAdapter
dbProvider = "PROVIDER=Microsoft.ACE.OLEDB.12.0;"
dbSource = "Data Source = C:\Documents and Settings\Desktop \studentmarks.accdb"
con.ConnectionString = dbProvider & dbSource
con.Open()
Dim student As String = ""
Dim course As String = ""
Dim grade As String = ""
Dim defaultSQL As String = "SELECT * FROM studentfile "
Dim WhereClause As String = ""
Dim StudentCourseGrade As String
'Students---------------------------------------------
For Each stu In studentList.SelectedItems
StudentCourseGrade = "(student='" & stu & "'"
For Each crs In courselist.SelectedItems
StudentCourseGrade = StudentCourseGrade & " AND course = '" & crs & "'"
For Each grd In gradeList.SelectedItems
StudentCourseGrade = StudentCourseGrade & " AND grade = '" & crs & "'"
Next
Next
StudentCourseGrade = StudentCourseGrade & ")"
If WhereClause.Length = 0 Then
WhereClause = "WHERE " & StudentCourseGrade
Else
WhereClause = " OR " & StudentCourseGrade
End If
Next
'Students---------------------------------------------
Dim SQL As String = defaultSQL & WhereClause
da = New OleDb.OleDbDataAdapter(sql, con)
da.Fill(ds, "topclass")
Dim view1 As New DataView(tables(0))
source1.DataSource = view1
DataGridView1.DataSource = view1
DataGridView1.Refresh()
DataGridView1.DataSource = view1
DataGridView1.Refresh()
Dim cnt As Integer
cnt = DataGridView1.Rows.Count
TextBox1.Text = cnt - 1
Dim dayclass As String = TextBox1.Text
TextBox8.Text = dayclass
con.Close()
End Sub
Hth
Chicken
I am attempting to make a hotel booking system. However the availability has got me a bit confused. I have about 15 buttons which I am able to save the number to the database but when the form loads/ date changed. I need the button to stay red and be unclickable. For example if I had a room 11 booked from 3/06/17 to 5/06/17 then I'd need the button to remain red from the 3/06/17 to 4/06/17 since the room is able to still be booked on the 5/06/17 after cleaning. I hope this makes sense. Below is the code I am using to try to do this. The code does run however the button does not turn red.
I was thinking does my SQL statement need to be changed but I'm not too sure. I'm pretty new to coding so an explanation would be helpful. Thanks.
Private Sub ReadRecords()
Dim btn As Button = Nothing
Dim BookingFound As Boolean = False
Using MyConn As New OleDbConnection
MyConn.ConnectionString = connString
MyConn.Open()
Dim check As String = "SELECT COUNT(*) FROM [BookingInformation] WHERE [Date In] = '" & dtpDateIn.Value.Date & "' AND [Date Out] = '" & dtpDateOut.Value.Date & "'"
Dim BookingExists As Boolean = False
Dim command As OleDbCommand = New OleDbCommand(check, MyConn)
Using reader As OleDbDataReader = command.ExecuteReader()
While reader.Read()
If reader(0) = 0 Then
BookingExists = False
Else
BookingExists = True
End If
End While
End Using
If BookingExists = True Then
Dim getData As String = "SELECT * FROM [BookingInformation] WHERE [Date Out] = '" & dtpDateOut.Text & "'"
Dim command2 As OleDbCommand = New OleDbCommand(getData, MyConn)
Using reader As OleDbDataReader = command2.ExecuteReader()
While reader.Read()
BookingFound = True
strDateIn = reader("Date In").ToString()
strDateOut = reader("DateOut").ToString
strRoomNumber = reader("Room Number").ToString
End While
If BookingFound = True Then
btn.BackColor = Color.Red
End If
End Using
End If
MyConn.Close()
End Using
End Sub
Private Sub Room_Booking_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ReadRecords()
End Sub
You should make your access database understand your input as date, access database is very sensitive to datatypes, for example if you write
"SELECT * FROM [user_tb] WHERE user_id=1"
Your code will work fine if your user_id data type is autonumber.
so try
Dim getData As String = "SELECT * FROM [BookingInformation] WHERE [Date Out] = #" & dtpDateOut.Text & "#"
Instead of
Dim getData As String = "SELECT * FROM [BookingInformation] WHERE [Date Out] = '" & dtpDateOut.Text & "'"
That is replace ' with #
I'm reading from a SQL database and depending on the fields I check I need to update a different field in that same table. I'm looping through the dataset and trying to send an UPDATE back while looping. It worked on my TEST table but isn't working for my production table. When I execute the "ExecuteNonQuery" command, I get a timeout expired error. If I actually close the first connection and then call the ExecuteNonQuery it runs instantly.
Here's the code...
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim sqlConn As New SqlConnection
Dim sqlComm As New SqlCommand
Dim sqlDR As SqlDataReader
sqlConn.ConnectionString = "Data Source=10.2.0.87;Initial Catalog=Inbound_Orders_DB;User ID=xxxxx;Password=xxxxxx;"
sqlConn.Open()
sqlComm.CommandText = "SELECT * FROM RH_Orders where Order_DateTime is NULL ORDER by Order_Date DESC"
sqlComm.Connection = sqlConn
sqlDR = sqlComm.ExecuteReader
If sqlDR.HasRows Then
While sqlDR.Read
If Trim(sqlDR("Order_Date")) <> "" Then
Dim order_Date As String = Trim(sqlDR("Order_Date"))
Dim order_DateTime As String = ""
If Len(order_Date) = 14 Then
order_DateTime = order_Date.Substring(0, 4) & "-" & order_Date.Substring(4, 2) & "-" & order_Date.Substring(6, 2) & " "
order_DateTime = order_DateTime & order_Date.Substring(8, 2) & ":" & order_Date.Substring(10, 2) & ":" & order_Date.Substring(12, 2)
Dim myId As String = sqlDR("ID")
Dim sqlConn2 As New SqlConnection
Dim sqlComm2 As New SqlCommand
sqlConn2.ConnectionString = "Data Source=10.2.0.87;Initial Catalog=Inbound_Orders_DB;User ID=xxxx;Password=xxxx;"
sqlConn2.Open()
sqlComm2.CommandText = "UPDATE [RH_Orders] SET order_DateTime = '" & order_DateTime & "' WHERE ID=" & myId
sqlComm2.Connection = sqlConn2
sqlComm2.ExecuteNonQuery()
sqlConn2.Close()
End If
End If
End While
End If
End Sub
End Class
Use parametrized queries and don't concatenate strings, then use a SqlParameter with SqlDbType.Datetime and assign a real DateTime instead of a formatted string.
But maybe it would be more efficient here to fill a DataTable with SqlDataAdapter.Fill(table), loop the table's Rows, change each DataRow and use SqlDataAdapter.Update(table) to send all changes in one batch after the loop. No need for the SqlDataReader loop.
For example (untested):
Using con = New SqlConnection("Data Source=10.2.0.87;Initial Catalog=Inbound_Orders_DB;User ID=xxxxx;Password=xxxxxx;")
Using da = New SqlDataAdapter("SELECT * FROM RH_Orders where Order_DateTime is NULL ORDER by Order_Date DESC", con)
da.UpdateCommand = New SqlCommand("UPDATE RH_Orders SET order_DateTime = #order_DateTime WHERE ID = #Id", con)
da.UpdateCommand.Parameters.Add("#order_DateTime", SqlDbType.DateTime).SourceColumn = "order_DateTime"
Dim table = New DataTable()
da.Fill(table)
For Each row As DataRow In table.Rows
Dim orderDate = row.Field(Of String)("Order_Date")
Dim orderDateTime As DateTime
If DateTime.TryParse(orderDate.Substring(0, 4) & "-" & orderDate.Substring(4, 2) & "-" & orderDate.Substring(6, 2), orderDateTime) Then
row.SetField("order_DateTime", orderDateTime)
End If
Next
da.Update(table)
End Using
End Using
Side-note: Instead of building a new string "2017-01-31" from "20170131" you could also use DateTime.TryParseExact:
DateTime.TryParseExact("20170131", "yyyyMMdd", nothing, DateTimeStyles.None, orderDateTime)
How can I make this work?
Private Sub ListView_MouseClick(sender As Object, e As MouseEventArgs) Handles ListView.MouseClick
conndb = New OleDbConnection
conndb.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Database1.accdb"
Try
conndb.Open()
Dim str As String
str = "Select * FROM customer WHERE CustomerID = '" & ListView.FocusedItem.Text & "'"
COMMAND = New OleDbCommand(str, conndb)
dr = COMMAND.ExecuteReader
If dr.Read = True Then
txtID.Text = dr("CustomerID")
txtFirstName.Text = dr("FirstName")
txtSurname.Text = dr("Surname")
txtAddress.Text = dr("Address")
txtCN1.Text = dr("ContactNo1")
txtCN2.Text = dr("ContactNo2")
txtEmail.Text = dr("EmailAddress")
txtRemarks.Text = dr("Remarks")
txtDebtStatus.Text = dr("DebtStatus")
txtDownPay.Text = dr("DownPayment")
txtDebtBal.Text = dr("DebtBal")
txtCustomerDate.Text = dr("Date")
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
Finally
conndb.Dispose()
End Try
End Sub
I need help on how can I make this run without errors, Im using ms access as my database source. There seems to be an error using this code, this code works perfectly fine with mysql but in ms access, it says data mistype error or something like that. Need your help, thanks
Remove the ' surrounding the field CustomerID in your query :
str = "Select * FROM customer WHERE CustomerID = '" & ListView.FocusedItem.Text & "'"
becomes :
str = "Select * FROM customer WHERE CustomerID = " & ListView.FocusedItem.Text
MS Access sees a string when you put an apostrophe, so there is a Type Mismatch Exception, because it is expecting a number...
However, this is a pretty bad idea as Parametrized queries are a better way of doing this (see : Why should I create Parametrized Queries ?)
Also, Use Using
So all in all, it's just another brick in the wall :
Private Sub ListView_MouseClick(sender As Object, e As MouseEventArgs) Handles ListView.MouseClick
Using conndb As New OleDbConnection
conndb.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Database1.accdb"
Try
conndb.Open()
Dim str As String
str = "Select * FROM customer WHERE CustomerID = #Customer"
Using COMMAND As New OleDbCommand(str, conndb)
COMMAND.Parameters.Add("#Customer", SqlDbType.Integer).Value = Integer.Parse(ListView.FocusedItem.Text)
dr = COMMAND.ExecuteReader
If dr.Read = True Then
txtID.Text = dr("CustomerID")
txtFirstName.Text = dr("FirstName")
txtSurname.Text = dr("Surname")
txtAddress.Text = dr("Address")
txtCN1.Text = dr("ContactNo1")
txtCN2.Text = dr("ContactNo2")
txtEmail.Text = dr("EmailAddress")
txtRemarks.Text = dr("Remarks")
txtDebtStatus.Text = dr("DebtStatus")
txtDownPay.Text = dr("DownPayment")
txtDebtBal.Text = dr("DebtBal")
txtCustomerDate.Text = dr("Date")
End If
End Using
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Using
End Sub
Take a look at this sample code that I put together a while back. You can probably learn a lot from this.
Private Sub TextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles TextBox1.TextChanged, TextBox1.Click
Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\your_path\Desktop\Northwind_2012.mdb"
Dim selectCommand As String
Dim connection As New OleDbConnection(connectionString)
'selectCommand = "Select * From MyExcelTable where Fname = '" & TextBox1.Text & "'"
'"SELECT * FROM Customers WHERE Address LIKE '" & strAddressSearch & "%'"
'or ending with:
'"SELECT * FROM Customers WHERE Address LIKE '%" & strAddressSearch & "'"
selectCommand = "Select * From MyExcelTable where Fname Like '" & TextBox1.Text & "%'"
Me.dataAdapter = New OleDbDataAdapter(selectCommand, connection)
With DataGridView1
.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.AllCells
.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.ColumnHeader
.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.ColumnHeader
End With
Dim commandBuilder As New OleDbCommandBuilder(Me.dataAdapter)
Dim table As New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
Me.dataAdapter.Fill(table)
Me.bindingSource1.DataSource = table
Dim data As New DataSet()
data.Locale = System.Globalization.CultureInfo.InvariantCulture
DataGridView1.DataSource = Me.bindingSource1
Me.DataGridView1.AlternatingRowsDefaultCellStyle.BackColor = Color.Aqua
Me.DataGridView1.AutoResizeColumns( _
DataGridViewAutoSizeColumnsMode.AllCells)
End Sub
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.