Specific condition against repeated datas...

Hi,

I wrote these codes to save datas (text and image). I need to reject the repeated name (for example: This name already exist). How can I do?

try
{
    byte[] img1 = null;
    FileStream fs1 = new FileStream(imgLoc1, FileMode.Open, FileAccess.Read);
    BinaryReader br1 = new BinaryReader(fs1);
    img1 = br1.ReadBytes((int)fs1.Length);
     string sql = "INSERT INTO intelflex1(ID, name,  age, imagem1)Values(" + txtID.Text + ",'" + txtName.Text  + "','" + txtAge + "','" + "',@img1)";
    if (conn.State != ConnectionState.Open)
        conn.Open();
    comm = new SqlCommand(sql, conn);
    comm.Parameters.Add(new SqlParameter("@img1", img1));
    int x = comm.ExecuteNonQuery();
    conn.Close();
    MessageBox.Show(x.ToString() + "saved successfully!");
}
catch (Exception ex)
{
    conn.Close();
    MessageBox.Show(ex.Message);
}

You can retrieve the count according to name.

Method 1.

public bool IsExist(string Name)
{
bool isValid=true;
using(SqlConnection con= new SqlConnection(cs)){
SqlCommand cmd= new SqlCommand("select count(*) from table where Name=@name",con);
cmd.Parameters.AddWithValue("@name",Name);
con.Open();
int res= Convert.ToInt32(cmd.ExecuteScalar());
if(res>0)
{
isValid=false;
}
return isValid;
}
}

then

try
{
if(IsExist()){
byte[] img1 = null;
FileStream fs1 = new FileStream(imgLoc1, FileMode.Open, FileAccess.Read);
BinaryReader br1 = new BinaryReader(fs1);
img1 = br1.ReadBytes((int)fs1.Length);
string sql = "INSERT INTO intelflex1(ID, name, age, imagem1)Values(" + txtID.Text + ",'" + txtName.Text + "','" + txtAge + "','" + "',@img1)";
if (conn.State != ConnectionState.Open)
conn.Open();
comm = new SqlCommand(sql, conn);
comm.Parameters.Add(new SqlParameter("@img1", img1));
int x = comm.ExecuteNonQuery();
conn.Close();
MessageBox.Show(x.ToString() + "saved successfully!");
}else
{
MessageBox.Show("Name already Exist");
}
}
catch (Exception ex)
{
conn.Close();
MessageBox.Show(ex.Message);
}

Method 2. Make the Name column unique key in the Database, so the duplicate name will throw an error that will be caught by your catch block and display.

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Sachin Singh5y ago
You can retrieve the count according to name.
Method 1.
public bool IsExist(string Name)
{
bool isValid=true;
using(SqlConnection con= new SqlConnection(cs)){
SqlCommand cmd= new SqlCommand("select count(*) from table where Name=@name",con);
cmd.Parameters.AddWithValue("@name",Name);
con.Open();
int res= Convert.ToInt32(cmd.ExecuteScalar());
if(res>0)
{
isValid=false;
}
return isValid;
}

}
then
try

            {
     if(IsExist()){

                byte[] img1 = null;

                FileStream fs1 = new FileStream(imgLoc1, FileMode.Open, FileAccess.Read);

                BinaryReader br1 = new BinaryReader(fs1);

                img1 = br1.ReadBytes((int)fs1.Length);

                 string sql = "INSERT INTO intelflex1(ID, name,  age, imagem1)Values(" + txtID.Text + ",'" + txtName.Text  + "','" + txtAge + "','" + "',@img1)";

                if (conn.State != ConnectionState.Open)

                    conn.Open();

                comm = new SqlCommand(sql, conn);

                comm.Parameters.Add(new SqlParameter("@img1", img1));

                int x = comm.ExecuteNonQuery();

                conn.Close();

                MessageBox.Show(x.ToString() + "saved successfully!");
}else
{
MessageBox.Show("Name already Exist");
}

            }

            catch (Exception ex)

            {

                conn.Close();

                MessageBox.Show(ex.Message);

}
Method 2. Make the Name column unique key in the Database, so the duplicate name will throw an error that will be caught by your catch block and display.