I want to populate the result of an SQL count query on a Access database in a textbox showing how many results there are. For example I have a code number inputted into the database 200 time, i want the textbox to show 200.
Heres my code so far:
ID = DataGridView1.CurrentRow.Cells(0).Value
fn = DataGridView1.CurrentRow.Cells(1).Value
ln = DataGridView1.CurrentRow.Cells(2).Value
SKU = DataGridView1.CurrentRow.Cells(4).Value
FC = DataGridView1.CurrentRow.Cells(5).Value
Dim countNoTwo As String = "SELECT COUNT skuNo FROM table WHERE skuNo = " & SKU & ""
Dim connection As New OleDbConnection(duraGadgetDB)
Dim dataadapter As New OleDbDataAdapter(countNoTwo, connection)
Dim ds As New DataSet()
connection.Open()
dataadapter.Fill(ds, "dura")
connection.Close()
txtbox1.Text
How do i bind the result of the dataset to the txtbox1.Text?
First, do not use string concatenation to build sql commands
(reason=Sql Injection + Parsing problems)
Second, if your command returns only one single result you could use
ExecuteScalar
Third, use the Using statement to be sure that your connection and
commands are correctly disposed after use
Dim countNoTwo As String = "SELECT COUNT skuNo FROM table WHERE skuNo = ?"
Using connection As New OleDbConnection(duraGadgetDB)
Using command As New OleDbCommand(countNoTwo, connection)
command.Parameters.AddWithValue("#sku", SKU)
connection.Open()
Dim result = Convert.ToInt32(command.ExecuteScalar())
txtbox1.Text = result.ToString
End Using
End Using
Try this
Dim dt As DataTable = ds.Tables(0)
txtbox1.Text = dt.Rows(0).Item(0).ToString()
Related
Please give me a solution.
I think I made the query code wrong
Private Sub PopulateDataGridView()
Dim query = "select ITM,ITC,QOH,PRS FROM IFG (WHERE QOH > 0 AND ITM = #ITM OR ISNULL(#ITM, '') = '')"
Dim constr As String = "provider=Microsoft.Jet.OLEDB.4.0; data source=C:\Users\ADMIN2\Desktop; Extended Properties=dBase IV"
Using con As OleDbConnection = New OleDbConnection(constr)
Using cmd As OleDbCommand = New OleDbCommand(query, con)
cmd.Parameters.AddWithValue("#ITM", cbCountries.SelectedValue)
Using sda As OleDbDataAdapter = New OleDbDataAdapter(cmd)
Dim dt As DataTable = New DataTable()
sda.Fill(dt)
dataGridView1.DataSource = dt
End Using
End Using
End Using
End Sub
Syntax error in FROM clause.
contents of the database
It's a question about SQL syntax, really, and not so much vb.net or oledb.
You had two WHERE clauses, which is invalid SQL. Change the second WHERE to AND
Dim query As String = "select ITM,ITC,QOH,PRS FROM IFG WHERE QOH > 0"
query &= " AND ITM = #ITM"
By the way, since strings are immutable in vb.net, you should not build a string like that (first assigning to, then adding to) when you so clearly can avoid it because every concatenation creates a new string in memory. You can either use &, a StringBuilder, or one long string. For example, taking advantage of vb.net syntax to make a multiline string, you can change the vb.net to
Dim query = "
select ITM,ITC,QOH,PRS
FROM IFG
WHERE QOH > 0
AND ITM = #ITM"
which is [subjectively] much easier to read as a SQL query (add the proper parentheses based on your logic, of course!).
Based on your update, you need to add a parameter to the query. Here is a more or less complete example of a query with one parameter
Using con As New OleDbConnection("connection string")
Dim query = "
select ITM,ITC,QOH,PRS
FROM IFG
WHERE QOH > 0
AND ITM = #ITM"
Using cmd As New OleDbCommand(query, con)
cmd.Parameters.AddWithValue("#ITM", itmValue)
Using rdr = cmd.ExecuteReader()
For Each result In rdr.AsQueryable()
' do something with each result
Next
End Using
End Using
End Using
I am trying to create a system that will load items from a database. There are two comboboxes; combobox1 which loads items from database table 1 and combox2 which loads items from database table 2.
Both tables are in the same database.
Here is was I tried but when I run the system I get this error:
(Conversion from string "SELECT * FROM dbo.Dishes" to type 'Long' is not valid.)
Here is the code I'm using:
Dim connection As New SqlConnection("Server = DESKTOP-1373H91; Initial Catalog = MealPreOrderSystem; Integrated Security = True")
connection.Open()
Dim query As String = "SELECT * FROM dbo.Dishes" And "SELECT * FROM dbo.Desserts"
Dim cmd As SqlCommand
cmd = New SqlCommand(query, connection)
Dim reader As SqlDataReader
reader = cmd.ExecuteReader
While reader.Read
cbxType.Items.Add(reader.Item("MealName"))
cbxType.Items.Add(reader.Item("DessertName"))
End While
connection.Close()
In VB.NET,AND is an operator.It is used to perform conjunction between either Booleans or Integers/Doubles/any numeric expression.Lets take your query string as an example :
Dim query As String = "SELECT * FROM dbo.Dishes" And "SELECT * FROM dbo.Desserts"
You are using AND here to join 2 sentences/strings which wouldn't result in anything rather it is trying to cast it as a Long.
Try to execute this command in SQL and you won't find any luck :(.
Your statements are correct :
SELECT * FROM dbo.Dishes
SELECT * FROM dbo.Desserts
But the way you are trying to achieve your goals is incorrect :(.
To get the data from the database into your combobox, what you can do is either use two comboboxes with separated SQL Queries/SQL Commands or you can use one combobox where you add data from both the databases but separate them with some special characters such as a comma ,
A sample may look like :
With one combobox
Dim cmd1 as new SqlCommand("SELECT * FROM dbo.Dishes",connection)
Dim dr as SqlDatareader = cmd1.ExecuteReader
While dr.Read
mycombo1.Items.Add(dr(0)) ' Here 0 is the column count,change it as required
End while
Dim cmd2 as new SqlCommand("SELECT * FROM dbo.Desserts",connection)
Dim dr2 as SqlDatareader = cmd2.ExecuteReader
While dr2.Read
mycombo2.Items.Add(dr2(0)) ' Here 0 is the column count,change it as required
End while
With 1 combobox
Here it gets a bit complicated.Firstly you need to populate your combobox from the data received from the first dataReader.Then, when the 2nd datareader is reading the data , you need to update the existing data/Item of the combobox keeping the existing data/item but adding new data/item to each existing data/item(separating them with ,).
Sample :
Dim i as Integer
Dim cmd1 as new SqlCommand("SELECT * FROM dbo.Dishes",connection)
Dim dr as SqlDatareader = cmd1.ExecuteReader
While dr.Read
mycombo1.Items.Add(dr(0))
End while
Dim cmd2 as new SqlCommand("SELECT * FROM dbo.Desserts",connection)
Dim dr2 as SqlDatareader = cmd2.ExecuteReader
While dr2.Read
mycombo1.Items(i) = myconbo1.Items(i) & "," & dr2(0)
i = i + 1
End while
Now, NOTE THAT I AM USING MULTIPLE DATAREADERS WITH THE SAME CONNECTION ,SO YOU MAY NEED TO INCLUDE MultipleActiveResultSets=True IN YOUR CONNECTION STRING or ENCLOSE THE DATAREADERS IN USING STATEMENTS or CALL dataReader.Close AFTER EACH DATAREADER HAS COMPLETED READING FROM THE DATABASE
This will solve your issue :)
Looks like you don't know how to write SQL queries (and your VB syntax itself looks faulty - string AND string?).
Dim connection As New SqlConnection("Server = DESKTOP-1373H91; Initial Catalog = MealPreOrderSystem; Integrated Security = True")
Dim query As String = <cmdString>
SELECT MealName as Name FROM dbo.Dishes
union
SELECT DessertName as Name FROM dbo.Desserts
</cmdString>
Dim cmd As SqlCommand
Dim reader As SqlDataReader
connection.Open()
cmd = New SqlCommand(query, connection)
reader = cmd.ExecuteReader
While reader.Read
cbxType.Items.Add(reader.Item("Name"))
End While
connection.Close()
Note: You are saying 2 comboboxes but your code seemed to be loading all the items to a single combobox. If you really need 2 comboboxes then use 2 SqlCommand and Reader loops (actually it would be better if you simply have used Linq for this).
You should be a bit more specific on what columns you are pulling from the 2 tables. if they are similar, you could write a sql query to UNION ALL the fields with a simple control to identify which record came from which table.
Example of SQL command string:
"SELECT 'M' AS Ctl, MealName AS aName FROM dbo.Dishes " &
"UNION ALL " &
"SELECT 'D' AS Ctl, DessertName AS aName FROM dbo.Desserts"
As mentioned by many here already, it seems like you are referencing only 1 ControlBox to list the fields returned cbxType
below is the reader (adapted to 2 ComboBoxes):
While reader.Read
Select Case reader.Item("Ctl")
Case "M"
cbxMType.Items.Add(reader.Item("aName"))
Case "D"
cbxDType.Items.Add(reader.Item("aName"))
End Select
End While
Hope this helps
So I have a MS Access Database with 1 table (Records) and 2 fields in it ("RecordID" (Number), which is the primary key, and "LowRes" (OLE Object) which is a low Resolution image). There are about 100 records.
I/m trying to load the Access Table into a DataTable (ID_Table) in VB.net.
Code so far:
Dim cnString As String = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=SBS2257_ID.accdb;"
Dim theQuery As String = "SELECT [RecordID], [LowRes] FROM [Records];"
Using CN As New OleDbConnection(cnString)
Dim command As New OleDbCommand(theQuery, CN)
Using objDataAdapter = New OleDbDataAdapter(command)
Dim ID_Table As New DataTable
CN.Open()
Dim pictureData As Byte() = DirectCast(command.ExecuteScalar(), Byte())
Dim picture As Image = Nothing
Using stream As New IO.MemoryStream(pictureData)
picture = Image.FromStream(stream)
objDataAdapter.Fill(ID_Table)
End Using
End Using
End Using
However the "DirectCast" command fails when I tell it to look at more then 1 field in my SQL statement with a datatype mismatch (if I just do [LowRes] it does not throw a error). However, I get stuck again when trying to apply the result to the table via the objDataAdapter, it doesnt fill the table with anything? I also notice that "picture" only contains the first image in the database.
I could put this database query in a function using "WHERE RECORDID=..." and loop it manually building the table returning "picture" each time, but Id like to avoid running a function 100 times, esp one that access a database.
Is it possible to read the whole database that contains images and just load it directly into a Datatable in one big swoop?
EDIT: So I got this to work:
Dim strConnection As String = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=SBS2257_ID.accdb;"
Dim strSQL As String = "SELECT [RecordID], [LowRes] FROM [Records];"
Using objConnection = New OleDbConnection(strConnection)
Using objCommand = New OleDbCommand(strSQL, objConnection)
Using objDataAdapter = New OleDbDataAdapter(objCommand)
Dim objDataTable As New DataTable("IDs")
objDataAdapter.Fill(objDataTable)
Return objDataTable
End Using
End Using
End Using
how ever when I go to view row 0, col 1 which should be the first LowRes image via a .ToString Useing this code:
Private Sub PrintValues(ByVal table As DataTable)
For Each row As DataRow In table.Rows
For Each col As DataColumn In table.Columns
MsgBox(row(col).ToString())
Next col
Next row
End Sub
It just displays "System.Byte[]". It knows its a Byte datatype, but how do I display that in a picturebox?
The ExecuteScalar() executes the query, and returns the first column of the first row in the result set returned by the query.
as your query is
Dim theQuery As String = "SELECT [RecordID], [LowRes] FROM [Records];"
the first column is RecordID which is not a Byte().
you can change your query as following:
Dim theQuery As String = "SELECT [LowRes] FROM [Records];"
or you have to use other methods to get data from the database
Dim strSql As String = "SELECT [RecordID], [LowRes] FROM [Records]"
Dim dtb As New DataTable
Using cnn As New OleDbConnection(connectionString)
cnn.Open()
Using dad As New OleDbDataAdapter(strSql, cnn)
dad.Fill(dtb)
End Using
cnn.Close()
End Using
I hava a Table named DTR_Table it has 8 columns in it namely:
EmployeeID,Date,MorningTime-In,MorningTime-Out,AfternoonTime-In,AfternoonTime-Out,UnderTime,Time-Rendered.I want to read the column "AfternoonTime-In".
Following is my code. It reads my "AfternoonTime-In" field, but it keeps on displaying "Has Rows" even if there is nothing in that column.
How can I fix this?
Connect = New SqlConnection(ConnectionString)
Connect.Open()
Dim Query1 As String = "Select [AfternoonTime-Out] From Table_DTR Where Date = #Date and EmployeeID = #EmpID "
Dim cmd1 As SqlCommand = New SqlCommand(Query1, Connect)
cmd1.Parameters.AddWithValue("#Date", DTRform.datetoday.Text)
cmd1.Parameters.AddWithValue("#EmpID", DTRform.DTRempID.Text)
Using Reader As SqlDataReader = cmd1.ExecuteReader()
If Reader.HasRows Then
MsgBox("Has rows")
Reader.Close()
Else
MsgBox("empty")
End If
End Using`
After returning the DataReader you need to start reading from it if you want to extract values from your query.
Dim dt = Convert.ToDateTime(DTRform.datetoday.Text)
Dim id = Convert.ToInt32(DTRform.DTRempID.Text)
Using Connect = New SqlConnection(ConnectionString)
Connect.Open()
Dim Query1 As String = "Select [AfternoonTime-Out] From Table_DTR
Where Date = #Date and EmployeeID = #EmpID"
Dim cmd1 As SqlCommand = New SqlCommand(Query1, Connect)
cmd1.Parameters.Add("#Date", SqlDbType.DateTime).Value = dt
cmd1.Parameters.Add("#EmpID", SqlDbType.Int).Value = id
Using Reader As SqlDataReader = cmd1.ExecuteReader()
While Reader.Read()
MessageBox.Show(Reader("AfternoonTime-Out").ToString())
Loop
End Using
End Using
Note that I have changed the AddWithValue with a more precise Add specifying the parameter type. Otherwise, your code will be in the hand of whatever conversion rules the database engine decides to use to transform the string passed to AddWithValue to a DateTime.
It is quite common for this conversion to produce invalid values especially with dates
How do you use SQL to put data into an empty table? So far in my code I have taken the data from an SQL table and then have put it into a Text Box using the following code:
Dim query As String = "SELECT Pronunciation, Character FROM [Katakana List] WHERE Pronunciation='" & pronunciation & "';"
Dim instruction = New SqlCommand(query, sqlCon)
Dim da As New SqlDataAdapter
da.SelectCommand = instruction
da.Fill(Katakana)
Textbox1.text=DT.row(0)("column")
Now that the data is held in the text box, how would I do the reverse of this process to put the data into an empty table. It would help if someone could give me an example of the query I could use to put the data back in.
If you want update data which you get from query before, then use UPDATE-query
If you want insert brand new data then use INSERT - query
'For updating existing data
Dim query As String = "UPDATE [Katakana List] SET Character = #NewCharacter WHERE Pronunciation=#Pronunciation"
'For Inserting new data
Dim query As String = "INSERT INTO [Katakana List] (Character) VALUES (#NewCharacter);"
Using instruction As New SqlCommand(query, sqlCon)
'Better practice to use parameters in query
instruction.Parameters.AddWithValue("#Pronunciation", pronunciation)
instruction.Parameters.AddWithValue("#NewCharacter", Textbox1.text)
instruction.ExecuteNonQuery()
End Using
If you want to set the data in the textbox into datatable just do it like this :
DT.row(0)("column") = Textbox1.text
if you want to enter it into database create query to do so , something like this :
Dim query As String = "Insert Into TableName(col1) Values('"& Textbox1.text &"');"
Dim command = New SqlCommand(query, sqlCon)
command.ExecuteNonQuery()