Getting an error.. Please verify code.

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This is my code. I'm trying to transfer contents of arraylist within an arraylist in to a ACCESS database. i get the following error when I run it:No value given for one or more required parameters . i can't figure out what the problem is. I'ma newbie so please forgive my ignorance if there's a stupid mistake.

C#

string con = "Provider=Microsoft.ACE.OLEDB.12.0;DataSource=|DataDirectory|\\Actual1.accdb";
OleDbConnection cn = new OleDbConnection(con);
                   
for (i = 0; i <= 3; i++)
{
  for (j = 0; j <= 3; j++)
  {
    string column_name = "cl" + i;
    OleDbCommand cmd = new OleDbCommand("Update Table1 set "+column_name+"="+str[i][j]+" where ID="+i+"", cn);
    cmd.Connection.Open();
    cmd.ExecuteNonQuery();
    cmd.Connection.Close();
  }
}

error occurs when cmd.executenonquery(); is executed.
column_name is cl0.
i=0.
j=0.

Posted 21-Sep-14 1:58am

Tejas Shastri

Updated 21-Sep-14 2:25am

v5

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Comments

BillWoodruff 21-Sep-14 8:05am

Set a break-point in the inner for loop, and single-step through the code when you hit the breakpoint. Modify your question here to include the information about where the error occurs.

[no name] 21-Sep-14 8:05am

Debug it and find out what the values of column_name, str, i, and j are at the time of the error. We can't do that for you.

2 solutions

Solution 3

On SQL injection, please see: http://en.wikipedia.org/wiki/SQL_injection[^].

This is how it works: http://xkcd.com/327[^]. :-)

The idea is: the user can enter a fragment of SQL code in the UI. Please see my past answers:
EROR IN UPATE in com.ExecuteNonQuery();[^],
hi name is not displaying in name?[^].

This is what you should use: http://msdn.microsoft.com/en-us/library/ff648339.aspx[^].

—SA

Posted 23-Sep-14 21:01pm

Sergey Alexandrovich Kryukov

Comments

Espen Harlinn 30-Sep-14 17:07pm

I see little Bobby is still doing well ...
BTW: a 5 :-)

Sergey Alexandrovich Kryukov 30-Sep-14 17:12pm

Probably, little Bobby Tables keeps screwing up the data, giving a little lesson to the sloppy developers over and over.
Thank you, Espen. How have you been all this time? Glad to hear from you.
—SA

Espen Harlinn 30-Sep-14 17:28pm

Just had a much needed 3 week holiday, and this is my last day at Goodtech :-)

Tomorrow will be my first official day as chief architect at Powel - I've been working with them for more than a year now - and it's been a great experience. So now we're looking for a decent place to live in Trondheim.

I sincerely hope all is well with you and that you're having a good time too.

Sergey Alexandrovich Kryukov 30-Sep-14 17:56pm

Ah... Congratulations... I guess. Do you mean you're supposed to move?
I recently had one shorted vacation, some 10 days, but they give me about a month (which is very long for US, where most people have no more that 2 weeks); in an hour, will probably arrange another 2-day vacation, due to important reason: next agricultural fair which is hard to reach from home.
—SA

Espen Harlinn 30-Sep-14 18:12pm

>> Ah... Congratulations... I guess
No need to guess: http://www.powel.com

>> Do you mean you're supposed to move?
Yes - we will be moving to Trondheim.

Powel is a spin-off from the Norwegian Electric Power Research Institute (EFI), and used to be a part of the SINTEF Group, which is, by far, the largest research organization here in Norway.

>> but they give me about a month
Good for you :-)

>> due to important reason: next agricultural fair
Now I'm getting curious ...

Sergey Alexandrovich Kryukov 30-Sep-14 18:48pm

All right, wish you high Norwegian power. :-)

If you are curious, in my opinion, agricultural fairs are most interesting regular events in New England. We always try to visit all we can reach, but we hardly can make for more then some 3 of them, for on of them. The best one, we try to take into account while planning vacation, to pay a day of visit or two, but this season we skipped it, because I had to shift vacation into September; it was a bit rainy couple of days, so did not swim in cold mounting rivers and lakes every days, but only some 7 days of 10, along with some hiking; still great One fair was on last weekend, so we want another one (3rd in this year). Did you see this American movie: http://en.wikipedia.org/wiki/Babe_%28film%29? It shows this very kind of fair. Repertoires are somewhat different; people can see horse show, horse-driven and bull-driven obstacle course, pig scrambling (most hilarious event), draft horse pulling competitions (most passionate thing), some kind of races, herding show with trained dogs, farm animal shows in different classes, and a lot more. Some good shopping, food. But most importantly, you can get close to any animals, talk with farmers. All my family likes those animals, especially my daughter. It all starts in the morning and even the competitions continue to the late night. (Farmers almost don't sleep these days.) Each fair takes several days, up to a week, but we hardly can spend more then 1-2 days at one...

—SA

Espen Harlinn 1-Oct-14 2:55am

Thanks :-)

Trekking is a brilliant way to spend your holidays - this year we went trekking into the mountains surrounding Voss here in Norway.

I haven't seen that movie, and I've never visited a country fair like the one you're describing - and it sounds like something we would enjoy though.

Sergey Alexandrovich Kryukov 1-Oct-14 12:06pm

:-)

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OriginalGriff · Accepted Answer · 2014-09-21T02:09:00

Solution 2

Probably, it has to do with the content on your str array.
It's very dangerous to do it that way: Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.
The changes are that will cure your problem at the same time:

C#

OleDbCommand cmd = new OleDbCommand("Update Table1 set "+column_name+"=@CL where ID="+i+"", cn);
cmd.Parameters.AddWithValue("@CL", str[i][j]);
cmd.Connection.Open();
cmd.ExecuteNonQuery();

Technically, the ID should be a parameter as well, but since it's an int it's not a problem.But the text string for the column content could be anything.

Posted 21-Sep-14 2:09am

OriginalGriff

Comments

Tejas Shastri 21-Sep-14 8:21am

Now there's another error:
"Index was out of range. Must be non-negative and less than the size of the collection"

What index is the compiler talking about??

OriginalGriff 21-Sep-14 8:46am

Either "i" or "j" in "str[i][j]" - you need to look at your str array and see how big it is. Since it's a jagged array (the "j" dimensions don't all have to be the same for the different values of "i") it's quite likely that the for loop(s) need changing to reflect the "real" sizes.
And there is a good chance that you meant to use "j" instead of "i" for your ID value as well! :laugh: (But that won't cause an error message, just rubbish in your DB.)

Tejas Shastri 21-Sep-14 9:04am

fixed it.. thanks :)

OriginalGriff 21-Sep-14 9:21am

You're welcome!