question on database query - C# Discussion Boards

Re: Setting value in installer and reading at runtime

6-Dec-07 17:48

you can store the user option in registry or in a config file, if you were not planning to write file, registry may be a choice.

I.explore.code6-Dec-07 17:52

I.explore.code

6-Dec-07 17:52

I believe, a strong solution is indeed what you are trying to avoid....u get it.."FILES"....

You can write the installation settings onto a text file and keep it hidden somewhere on the user machine, thts one of the best ways, really.

Alternatively, you can use windows registry to store the installation settings which is suppposedly the best way and the usual way other applications store settings during installation.

I havent tried the latter approach though and you may have to refer MSDN for this, u can get the complete code for your kinda requirements on MSDN.

Files have been my favorite way out for quite some time now. Smile | :)

question on database query

angels7776-Dec-07 16:57

6-Dec-07 16:57

hi.. the bottom code work very well.. but i have a few questions here..
for that code below..
1) i did not declare any connectionstring
2) i did not call any sqlcommand query e.g. "select name from ..."

is the way i do below good or bad? will it make things slow? because i did not specify the query "select name from.." .. , so the system will take time to take out all the data ?? instead of specify to my query?

there are so many ways to do that .. e.g databinding to textbox.. so compared to this below?

     void call_textbox()<br />
        {<br />
            DataTable store = new DataTable();<br />
            father.Fill(son.table);<br />
            store = son.table;<br />
<br />
            if (listBox1.SelectedIndex != -1)<br />
            {<br />
                //MessageBox.Show(store.Rows[listBox1.SelectedIndex].ItemArray[0].ToString());<br />
                foreach (DataRow row in store.Rows)<br />
                {                    <br />
                    if (row[0].ToString() == store.Rows[listBox1.SelectedIndex].ItemArray[0].ToString())<br />
                    {<br />
                        name.Text = row[1].ToString();<br />
                        address.Text = row[2].ToString();<br />
                        phone.Text = row[3].ToString();<br />
                    }<br />
                  <br />
<br />
                }<br />
            }<br />
<br />
        }

Jacky Yiu6-Dec-07 17:44

6-Dec-07 17:44

are you want to select the record from the DataTable that the row index = listBox1.SelectedIndex????

if so, why not
DataRow row = store.Rows[listBox1.SelectedIndex];
name.Text = row[1].ToString();
...

And there has a RowFilter properties in DataView(or DataTable.DefaultView), you can use it for filter any record you want...

check it out in MSDN:
http://msdn2.microsoft.com/en-us/library/system.data.dataview.rowfilter.aspx[^]

angels7776-Dec-07 18:06

6-Dec-07 18:06

thanks for reply.. anyway..my question is not on the listbox coding..

i have a few questions here..
for that code..
1) i did not declare any connectionstring
2) i did not call any sqlcommand query e.g. "select name from ..."

because if we specify the sqlcommand, will it save time to look for the data that we want instead of doing that in datatable like what i did above..??

why i did not declare the conntectionstring also can work? i did not declare the Using System.sqlclient..

which way is better ?

Jacky Yiu6-Dec-07 22:15

6-Dec-07 22:15

1) the connectionString has been stored in Properties.settings.
2) if you were drag and drop the datatable in to your program, SELECT, UPDATE, DELETE, INESRT Command will generate to you automatically...

Depends on the usage in your program, if you will handle all sql command, it should be "faster".
but if the record is not larger than 100,000. I don't think there has too much different. But development time Poke tongue | ;-P

angels7776-Dec-07 23:09

6-Dec-07 23:09

thanks.. so which mean the way i did is faster in development time ??

angels7777-Dec-07 19:50

7-Dec-07 19:50

i has also posted before to other forum.. what they said was the way i did will be slowing down eveyrthing..

angels7779-Dec-07 0:43

9-Dec-07 0:43

anyone?

Jacky Yiu9-Dec-07 15:11

why update data is wrong..

9-Dec-07 15:11

Sorry for late reply.

If you want to have a faster development time, you have to use the predefine or auto-gen code for your development, it will slow down the work, but it save in coding.

But if you have time to design a better software structure, it will take time but faster in performance.

It's depends on your choice.

angels7776-Dec-07 16:33

6-Dec-07 16:33

hi i use the below code to update..

DataTable store = new DataTable();
store = son.Table1;

father.Update(name.Text, ......)

but visual prompt me soemthing weird when i put " , " after name.text

in my Table1 only have "id, name, address" .

why after "," it prompt me update(string name, string address, int Original_ID, string Origianl_name, string Original_address, int ID)

i cant update if i din all those things.. something is wrong with my database.. ? i checked.. it shown only 3 fields

Jacky Yiu6-Dec-07 17:36

6-Dec-07 17:36

if your "father" (is it a good variable name?? D'Oh! | :doh:

) mean SqlDataAdapter, why don't you update the whole dataset or datatable???

and SqlDataAdapter.Update will be execute the UpdateCommand that predefine in the SqlDataAdapter.UpdateCommand, did you set the command correctly??

angels7776-Dec-07 18:18

6-Dec-07 18:18

do u mean i need to add query for update for my dataset ? i did not set the command.. cos when i put " father. " after the . it shown me the update..

the update already there// ? should i add that query ??

angels7776-Dec-07 18:55

6-Dec-07 18:55

i try to add the update query at the tableadapter query configuration wizards. it show like this

<br />
UPDATE [Table1] SET [name] = @name, [address] = @address, [phone] = @phone WHERE (([id] = @Original_id) AND ((@IsNull_name = 1 AND [name] IS NULL) OR ([name] = @Original_name)) AND ((@IsNull_address = 1 AND [address] IS NULL) OR ([address] = @Original_address)) AND ((@IsNull_phone = 1 AND [phone] IS NULL) OR ([phone] = @Original_phone)));<br />
SELECT id, name, address, phone FROM Table1 WHERE (id = @id)

why not like this

UPDATE       [Table1]<br />
SET          name = @name, address= @address, phone = @phone<br />
WHERE        (Id = @Original_Id); <br />
SELECT Id, name,address,phone FROM [User] WHERE (Id = @Id)

Jacky Yiu6-Dec-07 22:07