CODEWITHSUNDEEP
c#asp.netsqlado.net
user3120015
user3120015

Reputation: 181

How to check if a value already exists in my database and show a validation message

I have the below code, that connects to a Sql database and insert's data into a table :

string firstNameV = txtFname.Text;
string surnameV = txtSname.Text;
string emailV = txtEmail.Text;

SqlConnection conn = new   SqlConnection(ConfigurationManager.ConnectionStrings["myConnectionString"].ToString());

SqlCommand cmd = new SqlCommand();

cmd.CommandText = "INSERT INTO EmailSignUp (Title,FirstName,Surname,Email,EstablishmentType,Interests) VALUES (@Title,@FirstName,@Surname,@Email,@EstablishmentType,@Interests)";

cmd.Parameters.Add("@Title", SqlDbType.NVarChar).Value = title;
cmd.Parameters.Add("@FirstName", SqlDbType.NVarChar).Value = firstNameV;
cmd.Parameters.Add("@Surname", SqlDbType.NVarChar).Value = surnameV;
cmd.Parameters.Add("@Email", SqlDbType.NVarChar).Value = emailV;
cmd.Parameters.Add("@EstablishmentType", SqlDbType.NVarChar).Value = eType;
cmd.Parameters.Add("@Interests", SqlDbType.NVarChar).Value = ins;

cmd.Connection = conn;

conn.Open();

cmd.ExecuteNonQuery();
conn.Close();

How do I check if an email being entered in the "txtEmail" text box already exists in my database, in the email column and then alert message saying email already exists so it doesn't get inserted into my database?

Upvotes: 1

Views: 37380

Answers (5)

basheer
basheer

Reputation: 1

This works for me:

Create a function Called CheckMail(string email)

public bool CheckMail(string email)

        {
            SqlConnection con = new SqlConnection("Data Source=*******; Initial Catalog=Your Database Name; Persist Security Info=True;User ID=****; Password=******");

                SqlCommand cmd = new SqlCommand("select email from  Table Name where email='"+email+ "'",con);

                con.Open();

            SqlDataReader sdr = cmd.ExecuteReader();

            if (sdr.Read())
            {
                return false;
            }
            else
            {
                return true;
            }            
        }

 

Then Implement in Button Click as 

Pass Textbox value in function that were created..

 

if (CheckMail(EmailTxt.Text))  
                {

Write Your insert code to database 

}

else

{

Error Message or Alert to Show Already Exists in database

}

Upvotes: 0

Sinoy Siby
Sinoy Siby

Reputation: 39

Create a procedure on SQL server and check whether the name exists or not

    CREATE PROCEDURE Procedure_Name 
@mystring varchar(100),
@isExist bit out
AS
BEGIN
    if exists(select column1 from tblTable1 where column1=@mystring)
    begin
    select @isExist=1
    end
    else
    begin
    select @isExist=0
    end


END
GO

This is a sample procedure. If @isExist=1 that means the value exist.otherwise not. create a method to call this procedure and go on... Happy Coding

Upvotes: 0

Varun Kurumella
Varun Kurumella

Reputation: 71

Call this method in required textbox or area

public void EmailCheck()
    {
        string constring = ConfigurationManager.ConnectionStrings["ConnData"].ConnectionString;
        SqlConnection con = new SqlConnection(constring);
        SqlCommand cmd = new SqlCommand("Select * from EmailSignUp where EmailId= @EmailId", con);
        cmd.Parameters.AddWithValue("@EmailId", this.txtEmail.Text);
        con.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            if (dr.HasRows == true)
            {
                MessageBox.Show("EmailId = " + dr[5].ToString() + " Already exist");
                txtEmail.Clear();
                break;
            }
        }

    }

Upvotes: 6

SRJ
SRJ

Reputation: 198

Call a stored Procedure and inside the stored procedure you can check before insert

 IF NOT EXISTS(SELECT * FROM EmailSignUp WHERE Email =@email)   
 Begin
insert query here
 end

In another way you can check it in text changed event also

Upvotes: 0

voddy
voddy

Reputation: 1000

Try this

cmd.CommandText = "IF NOT EXISTS(SELECT * FROM EmailSignUp WHERE Email = '" 
+ txtEmail.Text + "') 
BEGIN
INSERT INTO EmailSignUp (Title,FirstName,Surname,Email,EstablishmentType,Interests) VALUES (@Title,@FirstName,@Surname,@Email,@EstablishmentType,@Interests) 
END";

Upvotes: 0

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