how to validate if the first name and last name is already exist in my sql database

Question

0.00/5 (No votes)

See more:

how to validate if the first name and last name is already exist in my sql database i have error in temp = Convert.ToInt32(com.ExecuteScalar().ToString());

SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["registrationConnectionString"].ConnectionString);
                conn.Open();

                
                string check = "select count(*) from userdata where FirstName,LastName='" +   TextBoxFN.Text + TextBoxFN.Text +"'";
                SqlCommand com = new SqlCommand(check, conn);
                com.Parameters.AddWithValue("@FN", TextBoxFN.Text);
                com.Parameters.AddWithValue("@LN", TextBoxLN.Text);
                temp = Convert.ToInt32(com.ExecuteScalar().ToString());

                if (temp == 1)
                {

                    Label1.Text = "Student Already Exist";

                }

Posted 28-Jan-15 17:53pm

Member 11407981

Updated 28-Jan-15 18:03pm

v3

Add a Solution

Comments

Rajesh waran 29-Jan-15 0:21am

Then what is your problem? Label1 is showing error msg or not?

Member 11407981 29-Jan-15 1:58am

not showing any error on label 1

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

_Asif_ · Accepted Answer · 2015-01-28T18:22:00

Solution 1

Replace this line with

string check = "select count(*) from userdata where FirstName,LastName='" +   TextBoxFN.Text + TextBoxFN.Text +"'";

With this

C#

string check = string.formt("select count(*) from userdata where FirstName='{0}' AND LastName='{1}'", TextBoxFN.Text, TextBoxLN.Text);

Posted 28-Jan-15 18:22pm

_Asif_

Comments

Member 11407981 29-Jan-15 8:07am

thankyou i solve my problem with your code thanks a lot

Sujith Karivelil · Accepted Answer · 2015-01-28T18:22:00

Solution 2

You need not to use parameterized query since your query already contains values. so make your query as follows and then run it.

conn.Open();
string inputQuery= "select count(*) from userdata where FirstName='" + TextBoxFN.Text         + "' And LastName='" + TextBoxFN.Text +"'";
SqlCommand com = New SqlCommand(inputQuery, conn);
temp = Convert.ToInt32(com.ExecuteScalar().ToString());
if (temp >= 1) '<--- updated here
  {
    Label1.Text = "Student Already Exist";
  }

or else you can use parameterized query as :

string check = "select count(*) from userdata where FirstName='{FN}' AND LastName='{LN}'"
SqlCommand com = new SqlCommand(check, conn);
com.Parameters.AddWithValue("@FN", TextBoxFN.Text);
com.Parameters.AddWithValue("@LN", TextBoxLN.Text);
temp = Convert.ToInt32(com.ExecuteScalar().ToString());

Posted 28-Jan-15 18:22pm

Sujith Karivelil

Updated 28-Jan-15 20:17pm

v3

Comments

Rajesh waran 29-Jan-15 0:32am

This may leads to sql injection.Have a look at this link.
http://www.w3schools.com/sql/sql_injection.asp[^][^]

Rajesh waran 29-Jan-15 0:33am

Just now saw your updated answer

Sujith Karivelil 29-Jan-15 0:41am

now it solves the problem, isn't it?

Rajesh waran 29-Jan-15 0:55am

Yes,passing parameterised Query is right one.

Member 11407981 29-Jan-15 1:56am

i for got to say this code is in page load event, ill try your code but the problem is not validating in my sql database. and the label1 is not showing any error message. example database have a firstname (ron) and lastname is (logmao) when user registered at the same name my database have a duplicate name and last name

Sujith Karivelil 29-Jan-15 2:16am

Put break pint and then check the value of temp, if the table contains more than one row then the value of temp will not be `1`. that's why the Label1.Text not getting changed. see my updates in the answer

Member 11407981 29-Jan-15 7:21am

the problem is still there i have a duplicate name in my database when registering a same name.

Member 11407981 29-Jan-15 7:41am

SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["registrationConnectionString"].ConnectionString);
conn.Open();

string check = "select count(*) from userdata where FirstName='" + TextBoxFN.Text + "'";
SqlCommand com = new SqlCommand(check, conn);
com.Parameters.AddWithValue("@FN", TextBoxFN.Text);
temp = Convert.ToInt32(com.ExecuteScalar().ToString());

if (temp == 1)
{

Label1.Text = "Student Already Exist";

}

when i use this code to validate FirstName only its work. but when i adding LastName for validation its not working.

Member 11407981 29-Jan-15 8:07am

problem is solve thank you guys for helping me.