I have tried many different things but at this point I am stumped.
Public Function GetCust(email As String) As Integer
Dim cs As String = <connection string>
Dim conn As New MySqlConnection(cs)
Dim custId As Integer
Dim cust_query As String = "SELECT entity_id FROM customer_entity WHERE email = '#email'"
Dim com As New MySqlCommand(cust_query, conn)
Dim reader As MySqlDataReader
Try
conn.Open()
com.Parameters.Add("#email", MySqlDbType.String)
com.Parameters("#email").Value = email
reader = com.ExecuteReader
While reader.Read()
custId = reader.GetInt16(0)
End While
MsgBox(custId)
Catch ex As Exception
MsgBox(ex.ToString)
End Try
Return custId
End Function
It should be pulling only one column and one row from a table so i should only have one value out of the query but it isn't entering the loop. Seems like its a syntax error on my part but can't seem to find it. Thanks in advance!
You should remove the quotes around the email parameter in the SQL string:
Dim cust_query As String = "SELECT entity_id FROM customer_entity WHERE email = #email"
This will generate SQL that looks like
WHERE email = ''myemail#mydomain.com''
when it should be
WHERE email = 'myemail#mydomain.com'
Related
I want to be able to read a value (in this case an Group ID). All the topics and tutorials I've watched/read take the data and put it into a textbox.
I don't want to put it in a textbox in this case; I want to grab the Group ID and then say:
If Group ID = 4 then login
Here is an image of the database.
Basically, but none of the tutorials I watch or the multiple forums. None of them take a a value and say if value = 4 then login or do something else.
If text = "1" Then
MysqlConn = New MySqlConnection
MysqlConn.ConnectionString =
"server='ip of server'.; username=; password=; database="
Dim READER As MySqlDataReader
Dim member_group_id As String
Try
MysqlConn.Open()
Dim Query As String
Query = "SELECT * FROM `core_members` where name='" & TextBox2.Text & "'"
Query = "SELECT * FROM `nexus_licensekeys` where lkey_key='" & TextBox1.Text & "'"
COMMAND = New MySqlCommand(Query, MysqlConn)
READER = COMMAND.ExecuteReader
Dim count As Integer
count = 0
While READER.Read
count = count + 1
End While
Here is what I have so far. I'm kind of new implementing mysql data with visual basic and only recently started to get into it. I'm not sure what comes next or how to even start with reading the group id etc.
As I said any help from here on out would be highly appreciated of how to read the group id and say if this group id = this number then do this or that. I'm sure you get the idea.
I divided the code into UI Sub, and Data Access Function that can return data to the UI. Your Event procedure code should be rather brief and the functions should have a single purpose.
Keep your database objects local to the method. This way you can have better control. The Using...End Using blocks ensure that your database objects are closed and disposed even if there is an error.
I leave it to you to add validation code. Checking for empty TextBox or no return of records.
I hope this serves as a quick introduction to using ADO.net. The take away is:
Use Parameters
Make sure connections are closed. (Using blocks)
Private ConnString As String = "server=ip of server; username=; password=; database="
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim GroupID As String = GetGroupID(TextBox1.Text)
If GroupID = "4" Then
'your code here
End If
Dim LocalTable As DataTable = GetLicenseKeysData(TextBox1.Text)
'Get the count
Dim RowCount As Integer = LocalTable.Rows.Count
'Display the data
DataGridView1.DataSource = LocalTable
End Sub
Private Function GetGroupID(InputName As String) As String
'Are you sure member_group_id is a String? Sure looks like it should be an Integer
Dim member_group_id As String = ""
'You can pass the connection string directly to the constructor of the connection
Using MysqlConn As New MySqlConnection(ConnString)
'If you only need the value of one field Select just the field not *
'ALWAYS use parameters. See comment by #djv concerning drop table
Using cmd As New MySqlCommand("SELECT g_id FROM core_members where name= #Name")
'The parameters are interperted by the server as a value and not executable code
'so even if a malicious user entered "drop table" it would not be executed.
cmd.Parameters.Add("#Name", MySqlDbType.VarChar).Value = InputName
MysqlConn.Open()
'ExecuteScalar returns the first column of the first row of the result set
member_group_id = cmd.ExecuteScalar.ToString
End Using
End Using
Return member_group_id
End Function
Private Function GetLicenseKeysData(InputName As String) As DataTable
Dim dt As New DataTable
Using cn As New MySqlConnection(ConnString)
Using cmd As New MySqlCommand("SELECT * FROM `nexus_licensekeys` where lkey_key= #Name;", cn)
cmd.Parameters.Add("#Name", MySqlDbType.VarChar).Value = InputName
cn.Open()
dt.Load(cmd.ExecuteReader())
End Using
End Using
Return dt
End Function
Is it possible to hide part of String.Format?
This my code:
'Select Product'
Try
MysqlConn.Close()
MysqlConn.Open()
Dim Query As String
Query = "select id, name,id_maker, id_types from product ORDER BY name ASC"
COMMAND = New MySqlCommand(Query, MysqlConn)
READER = COMMAND.ExecuteReader
While READER.Read
Dim sName = READER.GetString("name")
Dim sMaker = READER.GetString("id_maker")
Dim sTypes = READER.GetString("id_types")
Dim sId = READER.GetString("id")
'ComboBox1.Items.Add(sName)'
ComboBox1.Items.Add(String.Format("{0}|{1}|{2}|{3}", sName, sMaker, sTypes, sId))
End While
Catch ex As Exception
MessageBox.Show(ex.Message)
Finally
MysqlConn.Dispose()
End Try
'Select Product'
I want to hide {3} which is sId in the ComboBox, because later I need to use a query where the ComboBox1.Text is used and the id is necessary.
Maybe you could change the way you are assigning the data to the ComboBox.
First thing to do is change the query and use CONCAT:
SELECT id, CONCAT(name,'|',id_maker,'|',id_types) AS value FROM product ORDER BY name ASC
I would also implement Using:
Managed resources are disposed of by the .NET Framework garbage collector (GC) without any extra coding on your part. You do not need a Using block for managed resources. However, you can still use a Using block to force the disposal of a managed resource instead of waiting for the garbage collector.
You also don't need the READER. Instead load the data into a DataTable and assign that to the .DataSource property on the ComboBox.
Your code would look something like this:
Using con As New MySqlConnection(connectionString)
cmd As New MySqlCommand("SELECT id, CONCAT(name,'|',id_maker,'|',id_types) AS value FROM product ORDER BY name ASC", con)
con.Open()
Dim dt As New DataTable
dt.Load(cmd.ExecuteReader())
ComboBox1.DataSource = dt
ComboBox1.DisplayMember = "value"
ComboBox1.ValueMember = "id"
End Using
You can now get the id with this bit of code:
ComboBox1.SelectedValue.ToString()
And you can get the text with this bit of code:
ComboBox1.Text
Ok i use now that and works
Dim connetionString As String = Nothing
Dim connection As MySqlConnection
Dim command As MySqlCommand
Dim adapter As New MySqlDataAdapter()
Dim ds As New DataSet()
Dim i As Integer = 0
Dim sql As String = Nothing
'connetionString = "Data Source=ServerName;Initial Catalog=databasename;User ID=userid;Password=yourpassword"
'sql = "select id,name from product"
sql = "SELECT id, CONCAT(name,' | ',id_maker,' | ',id_types) AS value FROM product ORDER BY name ASC"
'connection = New MySqlConnection(connetionString)
connection = New MySqlConnection(ConfigurationManager.ConnectionStrings("xCollectibles.My.MySettings.xcollectiblesConnectionString").ToString)
Try
connection.Open()
command = New MySqlCommand(sql, connection)
adapter.SelectCommand = command
adapter.Fill(ds)
adapter.Dispose()
command.Dispose()
connection.Close()
ComboBox1.DataSource = ds.Tables(0)
ComboBox1.ValueMember = "id"
ComboBox1.DisplayMember = "value"
Catch ex As Exception
MessageBox.Show("Can not open connection ! ")
End Try
Thanks you..
I need to get all the values of each record in a table, this is so I can then add them to a text file log, a record per line, and then delete them from the database. I'm new to this and have searched how to add SQL query results to an array or a generic list, but I don't fully understand them.
All I have so far is:
Private Sub btnClearAll_Click(sender As Object, e As EventArgs) Handles btnClearAll.Click
conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=E:\Application Programming\Project\Issue Logger\Database\IssueLoggerDB.accdb"
Dim strSQl = "TRUNCATE TABLE CurrentJobs"
Dim commandInsert As New OleDbCommand
commandInsert.CommandText = strSQl
commandInsert.Connection = conn
commandInsert.Connection.Open()
commandInsert.ExecuteNonQuery()
Me.ReportViewer1.RefreshReport()
End Sub
This is for a Uni project, and above is how we have been to shown to do it, however nothing I have found while researching looks similar.
Feel free to use this procedure:
Private Sub DataTableToTextFile()
Dim connString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=E:\Application Programming\Project\Issue Logger\Database\IssueLoggerDB.accdb"
Using conn As OleDbConnection = New OleDbConnection(connString)
Dim dt As New DataTable
conn.Open()
'Change the query. It's not a good practice to use '*' in your select queries. Please, use the column names instead.
Dim dataAdapter As New OleDbDataAdapter("SELECT * FROM CurrentJobs", conn)
dataAdapter.Fill(dt)
'Change the path to your desired path
Dim exportPath As String = "C:\Logs\"
Dim exportFileName As String = "log.txt"
'If directory does not exists, create it
If Not Directory.Exists(exportPath) Then
Directory.CreateDirectory(exportPath)
End If
'Write data into the text file
Dim writer As New StreamWriter(exportPath + exportFileName)
Try
Dim sb As New StringBuilder
For Each row As DataRow In dt.Rows
sb = New StringBuilder
For Each col As DataColumn In dt.Columns
sb.Append(row(col.ColumnName))
Next
writer.WriteLine(sb.ToString())
Next
Catch ex As Exception
Throw ex
Finally
If Not writer Is Nothing Then writer.Close()
End Try
'Finally clean database table
Dim strSQl = "Delete From CurrentJobs"
Dim commandDelete As New OleDbCommand(strSQl, conn)
'execute
commandDelete.ExecuteNonQuery()
'close connection
conn.Close()
End Using
End Sub
I have run into this error while collecting data from a mysql database and placing it into a DataView control... This is my code:
Private Function PopulateActivity()
Dim loginStatement As String = "SELECT * FROM activity WHERE id = #userid"
Dim cmd As MySqlCommand = New MySqlCommand(loginStatement, mainconn)
cmd.Parameters.AddWithValue("#userid", LoggedInUser.ID)
Dim drMyAcount As MySqlDataReader = cmd.ExecuteReader()
Dim rowCount As Integer = 0
Dim rowAmount As Integer = 0
'gets count of rows returned from mysql query'
Using dt As New DataTable
dt.Load(drMyAcount)
rowAmount = dt.Rows.Count
End Using
'adds an entry for each item returned from the mysql query'
Do While rowCount < rowAmount
drMyAcount.Read() 'HERE IS WHERE ERROR OCCURS'
Dim tempDateTime As String = drMyAcount.Item("dateTime")
Dim tempInfo As String = drMyAcount.Item("info")
Dim tempBalChanges As String = drMyAcount.Item("balChange")
Dim tempToFrom As String = drMyAcount.Item("toFrom")
ActivityView.Rows.Add(tempDateTime, tempInfo, tempBalChanges, tempToFrom)
rowCount = rowCount + 1
Loop
drMyAcount.Close()
Return 0
End Function
I am unaware of why this is but it gives me an 'Invalid Attempt to Read when reader is closed' error one the:
drMyAccount.Read()
line...
I would appreciate any help on this topic! Thanks Much...
take out the dt.Load() , and counting of the rows prior to using datareader. DataReader has a built in property of .HasRows
if (drMyAcount.HasRows)
while (drMyAcount.Read())
Dim tempDateTime As String = drMyAcount.Item("dateTime")
Dim tempInfo As String = drMyAcount.Item("info")
Dim tempBalChanges As String = drMyAcount.Item("balChange")
Dim tempToFrom As String = drMyAcount.Item("toFrom")
ActivityView.Rows.Add(tempDateTime, tempInfo, tempBalChanges, tempToFrom)
rowCount = rowCount + 1 //you can still count rows in the loop
Loop
The MSDN documentation does not seem to specify, but apparently the DataTable.Load method closes the given IDataReader when it is done loading the data into the table. So, once you call dt.Load(drMyAcount), the drMyAcount will be closed.
I am trying to delete the users username from the database when s/he logs out. My code is the following which doesn't work. I Think it may have something to do with the connection string (database, password thing)
Private Sub Button1_Click_1(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim Query As String
Dim con As MySqlConnection = New MySqlConnection("Server=localhost;User ID=root;Password=*Mypassword*;Database=myusers")
con.Open()
Query = "Delete FROM users WHERE name =" + loginuser.Text
'Table = users
'Name = Varchar(20)
'loginuser.text = Name (username)
Dim cmd As MySqlCommand = New MySqlCommand(Query, con)
MsgBox(Query)
Dim i As Integer = cmd.ExecuteNonQuery()
If (i > 0) Then
MsgBox("Record is Successfully Deleted")
Else
MsgBox("Record is not Deleted")
End If
con.Close()
End Sub
You are not enclosing name value with quotes in your sql string,
Ex: Delete FROM users WHERE name = 'abcname'
Change your code to use parameters which is clean and secure way to pass values and you don't have to worry about quotes when working with string parameters
Query = "Delete FROM users WHERE name = #name"
Dim cmd As MySqlCommand = New MySqlCommand(Query, con)
MySqlCommand.Parameters.AddWithValue("#name",loginuser.Text)
String literals need to be enclosed in single quotes so your query should be:
Query = "Delete FROM users WHERE name = '" + loginuser.Text + "'"
Also concatenating a string into a SQL statement opens you up to SQL injection attacks (or even just think about someone putting "O'Brien" as the login name). You should always use parameters instead.