How I check if value is already exist in database when I insert values using C#

Question

1.00/5 (1 vote)

See more:

bağlanti.Open();
SqlCommand komut = new SqlCommand("insert into RezervasyonKayıt (Rezervasyon_İçerik,Yemek_Tercihi,Kişi_Sayısı,İçecek_Tercihi,Giris_Ekstraları,Yetkili_Kisi,Rezervasyon_Tarihi)values(@İçerik,@Yemek,@Kisi,@İcecek,@Giris,@Yetkili,@RezTarih)", bağlanti);
komut.Parameters.AddWithValue("@İçerik", comboBox1.SelectedItem);
komut.Parameters.AddWithValue("@Yemek", comboBox2.SelectedItem);
komut.Parameters.AddWithValue("@Kisi", comboBox3.SelectedItem);
komut.Parameters.AddWithValue("@İcecek", comboBox4.SelectedItem);
komut.Parameters.AddWithValue("@Giris", comboBox5.SelectedItem);
komut.Parameters.AddWithValue("@Yetkili", comboBox6.SelectedItem);
komut.Parameters.AddWithValue("@RezTarih", dateTimePicker1.Value);
komut.ExecuteNonQuery();
comboBox1.Text = "";
comboBox2.Text = "";
comboBox3.Text = "";
comboBox4.Text = "";
comboBox5.Text = "";
comboBox6.Text = "";
bağlanti.Close();
XtraMessageBox.Show("Randevu Başarıyla Kayıt Edilmiştir", "Bilgi Mesajı", MessageBoxButtons.OK, MessageBoxIcon.Information);

What I have tried:

before value saved in database check if Rezervasyon_Tarihi is exist in database

string cmd = @"SELECT COUNT(*) From RezervasyonKayıt WHERE Rezervasyon_Tarihi=@RezTarih))";
         SqlCommand komut = new SqlCommand(cmd, bağlanti);
          komut.Parameters.AddWithValue("@RezTarih", dateTimePicker1.Value);
          bağlanti.Open();
          int records = (int)komut.ExecuteScalar();

          if (records == 0)
          {
              komut.Parameters.Clear();
              cmd = @"insert into RezervasyonKayıt (Rezervasyon_İçerik,Yemek_Tercihi,Kişi_Sayısı,İçecek_Tercihi,Giris_Ekstraları,Yetkili_Kisi,Rezervasyon_Tarihi)values(@İçerik,@Yemek,@Kisi,@İcecek,@Giris,@Yetkili,@RezTarih)";
              komut = new SqlCommand(cmd, bağlanti);
              komut.Parameters.AddWithValue("@İçerik", comboBox1.SelectedItem);
              komut.Parameters.AddWithValue("@Yemek", comboBox2.SelectedItem);
              komut.Parameters.AddWithValue("@Kisi", comboBox3.SelectedItem);
              komut.Parameters.AddWithValue("@İcecek", comboBox4.SelectedItem);
              komut.Parameters.AddWithValue("@Giris", comboBox5.SelectedItem);
              komut.Parameters.AddWithValue("@Yetkili", comboBox6.SelectedItem);
              komut.Parameters.AddWithValue("@RezTarih", dateTimePicker1.Value);
              komut.ExecuteNonQuery();
              comboBox1.Text = "";
              comboBox2.Text = "";
              comboBox3.Text = "";
              comboBox4.Text = "";
              comboBox5.Text = "";
              comboBox6.Text = "";

              XtraMessageBox.Show("Randevu Başarıyla Kayıt Edilmiştir", "Bilgi Mesajı", MessageBoxButtons.OK, MessageBoxIcon.Information);
          }
          else
          {
              MessageBox.Show("Already Exist !");
          }

Posted 21-Nov-17 8:33am

Member 13533925

Updated 21-Nov-17 8:56am

v2

Add a Solution

1 solution

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)

ZurdoDev · Answer 1 · 2017-11-21T08:46:00

I suggest you change your sql and make it a stored procedure. It will be much easier to write that way. In the stored procedure you can use

SQL

IF EXISTS (SELECT 1 FROM table WHERE field = @value)
  BEGIN
    -- do the update
  END
ELSE
  BEGIN
   -- do the insert
  END

Or you can use the MERGE statement. MERGE (Transact-SQL) | Microsoft Docs[^]