Results 1 to 31 of 31

Thread: [RESOLVED] OleDbException Unhandled (No value given for one or more required parameters.)

  1. #1

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Resolved [RESOLVED] OleDbException Unhandled (No value given for one or more required parameters.)

    Hello ! I am making a project on Railway reservation system in which I want the user should have access to his booking history . The following code access records from two tables in the database . When I run this code for only one table ( accessing records from one table ) , it works fine but when I run this code for two tables , it gives me an error saying OleDbexception was unhandled ( No values given for more required parameters ) at
    Code:
      da.Fill(ds, "Table2")
    . I know this line is wrong , because it is only for one table but I don't know how to do it for two tables . Please help ! Thank you !


    Code:
     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            ds = New DataSet
            tables = ds.Tables
            da = New OleDbDataAdapter("Select P.Tnumber, P.Name , P.Age ,T.PNR_Number,  P.Train_Name , P.SeatNo , P.Berth , P.Coach_Number , T.Starting_Point , T.Destination , T.Departure , T.Arrival , T.Fare From Table1,Table2 Where P.Train_Name = T.Train_Name and P.Phone= TextBox1.Text ", MyConn)
            da.Fill(ds, "Table2")
    
            Dim view As New DataView(tables(0))
            source1.DataSource = view
            DataGridView1.DataSource = view

  2. #2
    .NUT jmcilhinney's Avatar
    Join Date
    May 2005
    Location
    Sydney, Australia
    Posts
    105,470

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Your SQL code is wrong. That SQL code gets sent to the database and executed there. What do you think the database is going to do with "TextBox1.Text"? Does it know anything about a TextBox on your form? I suggest that you follow the Blog link in my signature below and check out my post on Parameters In ADO.NET.

  3. #3

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thank you for replying . Do you mean that I have to convert my sql query into the parameterized query , then only it will work ? I know , I should not have used
    Code:
      P.Phone= TextBox1.Text
    but I don't know any other way in which I can write this . In my project , the records are fetched based on the phone number entered by the user . Now , I don't know I do I connect it with the sql . Please help ! :'(

  4. #4
    .NUT jmcilhinney's Avatar
    Join Date
    May 2005
    Location
    Sydney, Australia
    Posts
    105,470

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Quote Originally Posted by NancyCruz View Post
    Thank you for replying . Do you mean that I have to convert my sql query into the parameterized query , then only it will work ?
    You could make it work without parameters but using parameters is the proper and only good way to do it, so that's what you should do.
    Quote Originally Posted by NancyCruz View Post
    I don't know any other way in which I can write this .
    If only someone had provided directions to where you could find out. Oh look, someone did.

  5. #5

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thank you Could you also provide me directions on how can I fix this problem and remove this error . I would be very grateful to you . Please . Thank you !

  6. #6
    Super Moderator si_the_geek's Avatar
    Join Date
    Jul 2002
    Location
    Bristol, UK
    Posts
    41,502

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Using parameters should remove the error, and solve several other problems you haven't even noticed yet.

    Try the suggestion, and if you have problems getting it to work show us your attempt, and tell us what the issue is.

  7. #7

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Okay . I have tried writing this code but I think this is incorrect as it is giving me an error that connection property has not yet initialized.
    Code:
     
     Dim str As String
            ds = New DataSet
            tables = ds.Tables
            str = "Select  P.Tnumber, P.Name , P.Age ,T.PNR_Number,  P.Train_Name , P.SeatNo , P.Berth , P.Coach_Number , T.Starting_Point , T.Destination , T.Departure , T.Arrival , T.Fare From Table1,Table2 Where P.Train_Name = T.Train_Name and P.Phone = '" & TextBox1.Text & "'"
            Dim cmd As OleDbCommand = New OleDbCommand(str, MyConn)
                Try
                    cmd.ExecuteNonQuery()
                    cmd.Dispose()
    
    
                da.Fill(ds, "Table2")
    
                Dim view As New DataView(tables(0))
                source1.DataSource = view
                DataGridView1.DataSource = view
    
                MyConn.Close()
    
                Catch ex As Exception
                    MsgBox(ex.Message)
                End Try
    P.S - Actually , I have studied visual basic only in my last semester and that too just basics . In this semester , I have to make a big project on visual basic . When I went to the teacher who is my supervisor for asking all the doubts regarding to my project , my teacher told me that he has no idea of visual basic ( strange ! ) so , I am pretty much on my own for this project That's why I would be very grateful to you if you help me Thank you !

  8. #8
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Code:
    Dim dt As New Datatable
    
    Using cn As New OleDBConnection(MyConn)
     Using cmd As OleDBCommand = cn.CreateCommand
      Using da As New OleDBDataAdapter
       cmd.CommandText = "Select  P.Tnumber,P.Name ,P.Age ,T.PNR_Number,P.Train_Name ,P.SeatNo ,P.Berth ,P.Coach_Number,                                T.Starting_Point, T.Destination , T.Departure , T.Arrival , T.Fare From Table1 As P INNER JOIN Table2 As T ON P.Train_Name = T.Train_Name WHERE P.Phone = ?"
       Try
         cmd.Parameters.AddWithValue("p1",TextBox1.Text)
         da.SelectCommand = cmd
         da.Fill(dt)
       Catch ex As Exception
        'Do SOMETHING here, even if it is just showing a messagebox.
       End Try
      End Using
     End Using
    End Using
    That is roughly how I'd write it.

    1) The Using blocks ensure that the objects are cleaned up correctly, so you don't need to dispose of things.
    2) Every time you interact with a database, it should be in a Try...Catch block, because you just never know what happens.
    3) Parameters for OleDB queries are a bit goofy, because Access doesn't allow named parameters, but since you have only one, there's not so much to say about them.
    4) I'm not sure that I got the SQL correct, but I'm pretty sure that you didn't have it correct to start with. An Inner Join will be more efficient than the WHERE clause you were using, but since I don't know the relationships between the tables, I was kind of guessing as to how to build the join.
    My usual boring signature: Nothing

  9. #9

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thank you for replying . It now gives me an error saying "Error 1 Value of type 'System.Data.OleDb.OleDbConnection' cannot be converted to 'String' " What should I do now ?

  10. #10
    .NUT jmcilhinney's Avatar
    Join Date
    May 2005
    Location
    Sydney, Australia
    Posts
    105,470

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Quote Originally Posted by NancyCruz View Post
    Thank you for replying . It now gives me an error saying "Error 1 Value of type 'System.Data.OleDb.OleDbConnection' cannot be converted to 'String' " What should I do now ?
    If you're using Shaggy's code as is then the issue is presumably here:
    Code:
    Using cn As New OleDBConnection(MyConn)
    This is why you shouldn't just copy and paste code without thinking for yourself. In your previous code, your MyConn variable presumably refers to an OleDbConnection object. In Shaggy's code, he is creating an OleDbConnection object and assigning it to a variable `cn`. You don't create a connection object and pass it a connection object. You create a connection object and pass it a String; specifically a connection string. Shaggy is telling you to create a new connection object as part of the code that retrieves the data. If you're not going to do that then get rid of the part of Shaggy's code that creates the connection object and use your existing connection object. Do one or the other, not a combination of the two that doesn't work because it does neither.

  11. #11

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Sorry for my silly mistakes . As I have already told you that I had only studied visual basic in my last semester ( only basics !) and this year I have to make a big project with it . I have written the code , which I think is still wrong . The problem is that it is not giving me any error but it is not showing anything in the datagridview .
    Code:
        MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            Using cmd As OleDbCommand = MyConn.CreateCommand
                ds = New DataSet
                tables = ds.Tables
                Using da As New OleDbDataAdapter
                    cmd.CommandText = "Select  P.Tnumber,P.Name ,P.Age ,T.PNR_Number,P.Train_Name ,P.SeatNo ,P.Berth ,P.Coach_Number,  T.Starting_Point , T.Destination , T.Departure , T.Arrival , T.Fare  From Table1 As P INNER JOIN Table2 As T ON P.Train_Name = T.Train_Name WHERE P.Phone = ?"
    
                    Try
                        cmd.Parameters.AddWithValue("p1", TextBox1.Text)
                        da.SelectCommand = cmd
                        da.Fill(ds, "Table2")
                        Dim view As New DataView(tables(0))
                        source1.DataSource = view
                        DataGridView1.DataSource = view
    
                    Catch ex As Exception
                        'Do SOMETHING here, even if it is just showing a messagebox. 
                    End Try
    
    
                End Using
            End Using

  12. #12
    Super Moderator si_the_geek's Avatar
    Join Date
    Jul 2002
    Location
    Bristol, UK
    Posts
    41,502

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    This would be why it isn't showing any errors:
    'Do SOMETHING here, even if it is just showing a messagebox.
    That was an instruction for you to do something... you had something in post #7 that would work.

  13. #13

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thanks for replying ! I did the modification and still getting the error "No value given for one or more required parameters."
    Code:
      MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            Using cmd As OleDbCommand = MyConn.CreateCommand
                ds = New DataSet
                tables = ds.Tables
                Using da As New OleDbDataAdapter
                    cmd.CommandText = "Select  P.Tnumber,P.Name ,P.Age ,T.PNR_Number,P.Train_Name ,P.SeatNo ,P.Berth ,P.Coach_Number,  T.Starting_Point , T.Destination , T.Departure , T.Arrival , T.Fare  From Table1 As P INNER JOIN Table2 As T ON P.Train_Name = T.Train_Name WHERE P.Phone = ?"
    
                    Try
                        cmd.Parameters.AddWithValue("p1", TextBox1.Text)
                        da.SelectCommand = cmd
                        da.Fill(ds, "Table2")
                        Dim view As New DataView(tables(0))
                        source1.DataSource = view
                        DataGridView1.DataSource = view
    
                    Catch ex As Exception
                        MsgBox(ex.Message)
                    End Try
    
    
                End Using
            End Using

  14. #14
    Frenzied Member Gruff's Avatar
    Join Date
    Jan 2014
    Location
    Scappoose Oregon USA
    Posts
    1,293

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    As mentioned parameters are the way to go, however it is important to know how to join string variables and literal string in general.

    Start a new sample program.
    Place a textbox and a button on the form.
    Paste in this code and run the program.
    Code:
    Public Class Form1
    
    Public Sub Button1_Click(Sender as System.Object, e as EventArgs) handles Button1.Click
      Textboxt.Text = "Nancy" 
      messagebox.show("Hi Textbox1,text")
      messagebox.show("Hi " & Textbox1.text)
    End Sub
    
    End Form
    What you are seeing is the difference between a string literal and joining a string literal to a textbox.text string property.
    We use the ampersand to join strings in VB.

    Sorry if this skews things off topic. A lot of posts were made while I typed this.
    Last edited by Gruff; Apr 5th, 2015 at 08:59 AM.
    Burn the land and boil the sea
    You can't take the sky from me


    ~T

  15. #15

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thanks for replying ! So , you mean that something is wrong with the join operation ? If I correct that then my program will run ?

  16. #16
    Super Moderator si_the_geek's Avatar
    Join Date
    Jul 2002
    Location
    Bristol, UK
    Posts
    41,502

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    No, that is not related to your latest code at all - it is just something that you should understand.


    The error is unfortunately vague, and I can't see anything obviously wrong... I would recommend temporarily removing the Where clause and parameter, eg:
    Code:
                   cmd.CommandText = "Select  P.Tnumber,P.Name ,P.Age ,T.PNR_Number,P.Train_Name ,P.SeatNo ,P.Berth ,P.Coach_Number,  T.Starting_Point , T.Destination , T.Departure , T.Arrival , T.Fare  From Table1 As P INNER JOIN Table2 As T ON P.Train_Name = T.Train_Name"' WHERE P.Phone = ?"
    
                    Try
                        'cmd.Parameters.AddWithValue("p1", TextBox1.Text)
    This will allow you to see if the error is actually before the Where clause (if it is, fix it before adding the Where clause back in).

  17. #17
    Frenzied Member Gruff's Avatar
    Join Date
    Jan 2014
    Location
    Scappoose Oregon USA
    Posts
    1,293

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    If it were me, I'd also turn on Option Explicit and make sure intellisense is on as well.

    One difference I see is Nancy is using a dataset instead of a datatable.

    Personally I've never had a need to use a dataset so I could be wrong.
    Does the New() method for a dataset require a name?

    Maybe someone else can verify as I am at home on a chrome book and cannot test anything.
    Burn the land and boil the sea
    You can't take the sky from me


    ~T

  18. #18

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thanks everyone for replying ! Actually , the code I posted in the starting was working when I was using only one table but it gave me an error when I used two tables. So, I think something is wrong with my way of using two tables but I don't know what it is ?

  19. #19

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    One more thing I want to add is that when I used the code with only one table I didn't use any where clause . I just displayed all the columns !

  20. #20
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    No, that's ok. A dataset is nothing more than a collection of datatables. Since there is only one table, there is no reason to use a dataset, but there also isn't any harm in using a dataset. My example used just a datatable, but what she's done with a dataset looks right to me.

    One point that doesn't matter, is that there is no need to create a new dataview. Every datatable has one already called the DefaultView, so you could also just use Tables(0).DefaultView rather than creating a new one. I doubt that it makes any difference, though.

    The issue comes down to something in the SQL, and that something is probably a Typo at this point. Temporarily getting rid of the WHERE clause is just the first step at trying to figure out where the typo is. The other thing you need to do is make sure that all the names are correct. Are those really the field names? Are they spelled exactly as you have them (you can ignore capitalization, since that doesn't matter)? Do you really have tables named Table1 and Table2 (those aren't good names, since your names should be meaningful, but they ARE the default names for Access tables)?

    Another thing that you might try is changing from p.Name to p.[Name]. You would have to enclose the field name in square brackets if the name happens to be a keyword. Of all the names you have used, only Name seems likely to be a keyword, though Destination might be, as well.
    My usual boring signature: Nothing

  21. #21
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Wow, two posts while I was writing.

    You need to use whatever tables are necessary. That's not really a .NET question as much as it is a SQL query question, but we probably don't know enough about it, yet, to be able to say all that much.

    The way the query that I wrote is written, it is saying "Give me these fields for all records that have this phone number." The join is getting information from table 2 (which seems to have to do with timetables) for records in table 1 that have the phone number. But I don't know what table 1 is and I don't know what table 2 is, so I don't know if the relationship between the two makes sense. It seems to, from what you have written, but I don't really know.
    My usual boring signature: Nothing

  22. #22

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thanks everyone for replying . I checked my code with only one table first and found out something really strange ! When I use "Select *" , my code works fine and it displays all the columns in the datagridview but when I type selected fields , it gives me an error saying that "No value given for one or more required parameters." This code works fine for only one table -
    Code:
      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            ds = New DataSet
            tables = ds.Tables
            da = New OleDbDataAdapter("Select *  from Table2", MyConn)
            da.Fill(ds, "Table2")
            Dim view As New DataView(tables(0))
            source1.DataSource = view
            DataGridView1.DataSource = view
    
        End Sub
    Yes, all my field names are correct and table1 and table2 are the actual table names in my database . I know they aren't good but actually I just created those two tables hastily and have used them in the coding of my the modules . So, I think changing their names now , would be not that good as this one is the last module of my project ! Thanks !

  23. #23

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Could anyone of you tell how how to use this
    Code:
      da.Fill(ds, "Table2 ")
    for two tables , maybe this is also giving the problem ! Thanks !

  24. #24

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Okay , I figured the problem for the first table which was not displaying selected fields , When I enclose field names for only one table , it works fine ! But when I tried doing it for the two table code , it gives the same error !
    Code:
      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            Using cmd As OleDbCommand = MyConn.CreateCommand
                ds = New DataSet
                tables = ds.Tables
                Using da As New OleDbDataAdapter
                    cmd.CommandText = "Select  P.[Tnumber] ,P.[Name] ,P.[Age] ,T.[PNR_Number],P.[Train_Name] ,P.[SeatNo] ,P.[Berth] ,P.[Coach_Number],  T.[Starting_Point] , T.[Destination] , T.[Departure] , T.[Arrival] , T.[Fare]  From Table1 As P INNER JOIN Table2 As T ON P.[Train_Name] = T.[Train_Name] WHERE P.[Phone] = ?"
    
                    Try
                        cmd.Parameters.AddWithValue("p1", TextBox1.Text)
                        da.SelectCommand = cmd
                        da.Fill(ds, "Table2")
                        Dim view As New DataView(tables(0))
                        source1.DataSource = view
                        DataGridView1.DataSource = view
    
                    Catch ex As Exception
                        MsgBox(ex.Message)
                    End Try
    
    
                End Using
            End Using
    
        End Sub

  25. #25
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    You didn't need to wrap ALL the names in []. Only one or two of them were conflicting. Names like PNR_Number and Tnumber are always safe. Names that are actual words, like Name, Departure, or Destination could cause trouble because they might be keywords. Name is probably the only one you needed to wrap, but you can play with that, or not, to figure out which ones are keywords.

    Writing out the field names is considerably better than using *, so that's a good thing. Even if you really want ALL the fields, the engine does extra work for *, so it is always less efficient. So, good job with writing out the field names.

    To be clear: The error it is giving is "No value given for one or more required parameters."?

    It's an annoying error, because you are left to figure it out almost by trial and error. Here are the next steps that I see:

    1)Are you sure that both Table1 and Table2 have a field called Train_Name and that it is spelled EXACTLY as you have it (except for capitalization)?

    2) If so, then try commenting out the WHERE clause and see whether or not the problem goes away (that would isolate the issue to the WHERE clause.

    3) If that doesn't solve it, then remove everything from the SELECT statement except for P.[Tnumber]. If that makes the problem go away, then keep adding more fields back in until the problem shows up again, which will allow you to figure out which field is the problem. Of course, if removing all but one field does NOT solve the problem, then the problem is in what is left. Step 2 excluded the WHERE clause, step 3 would rule out the SELECT clause, so all that would be left would be the JOIN.

    This particular error can be very frustrating, and especially so because it is so unnecessary. The SQL parser has enough information to give you a pretty good idea where to look, but it simply doesn't, so you have to divide and conquer, or simply guess.
    My usual boring signature: Nothing

  26. #26

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thanks for replying ! This code works fine with only [Tnumber] ( I think because I am retrieving data from only one table )
    Code:
      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            Using cmd As OleDbCommand = MyConn.CreateCommand
                ds = New DataSet
                tables = ds.Tables
                Using da As New OleDbDataAdapter
                    cmd.CommandText = "Select  [Tnumber] from Table2 "
    
                    Try
                        'cmd.Parameters.AddWithValue("p1", TextBox1.Text)'
                        da.SelectCommand = cmd
                        da.Fill(ds, "Table2")
                        Dim view As New DataView(tables(0))
                        source1.DataSource = view
                        DataGridView1.DataSource = view
    
                    Catch ex As Exception
                        MsgBox(ex.Message)
                    End Try
    
    
                End Using
            End Using
    
        End Sub
    But when use these two fields that are from two different . It gives me the same error !
    Code:
      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            MyConn = New OleDbConnection
            MyConn.ConnectionString = connString
            Using cmd As OleDbCommand = MyConn.CreateCommand
                ds = New DataSet
                tables = ds.Tables
                Using da As New OleDbDataAdapter
                    cmd.CommandText = "Select  T.[Tnumber] , P.[Destination] from Table2, Table1 "
    
                    Try
                        'cmd.Parameters.AddWithValue("p1", TextBox1.Text)'
                        da.SelectCommand = cmd
                        da.Fill(ds, "Table2")
                        Dim view As New DataView(tables(0))
                        source1.DataSource = view
                        DataGridView1.DataSource = view
    
                    Catch ex As Exception
                        MsgBox(ex.Message)
                    End Try
    
    
                End Using
            End Using
    
        End Sub

  27. #27
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Well, yeah, but the query text is malformed. T and P are aliases for the tables, yet you didn't tell the query engine what T and P stand for. It shouldn't work for even one table, so I doubt you wrote it quite like that.

    Note that in the SQL I wrote earlier, I had Table1 As P. That is telling SQL that P stands for Table1, so it knows to replace P with Table1. I had a similar thing for Table2.

    What you could do would be

    "Select Table2.[Tnumber] , Table1.[Destination] from Table2, Table1 "

    and not use the aliases at all. By doing this, you are explicitly saying which table the fields are found in. As a general rule, I prefer not using aliases, because I find them to make it harder to read the SQL, but some people have such massive table names that they don't want to use the full table name, and there are queries where you HAVE to use aliases, such as a query that joins on the same table multiple times.
    My usual boring signature: Nothing

  28. #28

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    Thanks for replying ! I tried that also , but it is still giving me the same error

  29. #29
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    So, what does the actual code you are using look like now?
    My usual boring signature: Nothing

  30. #30

    Thread Starter
    Member
    Join Date
    Apr 2015
    Posts
    34

    Re: OleDbException Unhandled (No value given for one or more required parameters.)

    I changed the name of some fields in my table , like , where there was only name ( in Table2) , I changed it to P_Name , and did some modifications and rewrite the whole code again with these new fields also and my code works now !!! I want to thank each and everyone here on this forum who has taken his precious time to help me . Thank you very much everyone . I just can't express my gratitude towards everyone in few words . Thank you again !

  31. #31
    Super Moderator Shaggy Hiker's Avatar
    Join Date
    Aug 2002
    Location
    Idaho
    Posts
    35,242

    Re: [RESOLVED] OleDbException Unhandled (No value given for one or more required para

    That's a good rule to follow: Never use a single real word as the name for ANYTHING in programming. Not for field names, not for variables, not for class names. Generally, if you get a variable or class name that conflicts with a keyword, you won't be allowed to use that name, so the mistake won't be one you can make, but you are still living a bit risky. When it comes to a database, if you happen to use a name that conflicts...good luck finding it. The DB won't give you any help with that, even though it EASILY could. Some programming languages have the same problem: It won't work, but it won't tell you quite what you need to know to fix the problem.

    One interesting example that I encountered (but which has since been fixed) was the use of ID for the name of the ID field in a database. This caused no trouble in the database itself, nor in any query against the database. The problem was if you ever exported the information to a text file. Normally, such a file could be opened in Excel without any difficulty...unless the first two letters in the file were ID, in which case Excel would throw up a cryptic message and refuse to open the file.

    So, it's a good, general, rule to always fancy up the names in some way. Personally, I don't like underscores (though I occasionally use them) because they are harder to type than letters. So, we have fields like PName in some tables. That's just a matter of preference, though.
    My usual boring signature: Nothing

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  



Click Here to Expand Forum to Full Width