无法使用C＃更新我的SQL数据库

Question

I am working on a database with C# and searching in the database is no problem, i get the correct information when searching. Thou if i want to update my database with new Tigers (for an example) it wount update. My self cant see any problems with the code and i do not get any errors. Where can the problem be? This is the code:

    public void UpdateTigers(string[] array, string persNo)
    {
        //Creating the connection string.
        string connectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\Owner.mdf;Integrated Security=True";
        //Creating a connection to the database with the connection string value.
        using (SqlConnection con = new SqlConnection(connectionString))
        {
            //Opening the connection to the SQL database
            con.Open();
            //Creating a commands(querys) to be used.
            SqlCommand cmd = new SqlCommand("UPDATE Owner SET Tiger1=@tiger1 WHERE Personnummer=" + persNo, con);
            if (array[6] != "")
            {
                cmd = new SqlCommand("UPDATE Owner SET Tiger1=@tiger1, Tiger2=@tiger2 WHERE Personnummer=" + persNo, con);
            }
            if (array[7] != "")
            {
                cmd = new SqlCommand("UPDATE Owner SET Tiger1=@tiger1, Tiger2=@tiger2, Tiger3=@tiger3 WHERE Personnummer=" + persNo, con);
            }
            //Adding to the SqlCommand what @Name got for value.
            cmd.Parameters.AddWithValue("@tiger1", array[6]);
            if (array[6] != "")
                cmd.Parameters.AddWithValue("@tiger2", array[7]);
            if (array[7] != "")
                cmd.Parameters.AddWithValue("@tiger3", array[8]);
            //Sending the request to the database.
            cmd.ExecuteNonQuery();

            //No need for a con.Close() because the using statement closes it automatically.
        }

Answer 1

Do not cram all the CRUD in one method. create a method for each one and return true if the query ran successfully and false if otherwise. Example:

Use try catch. if there is no exception, then the query was ran successfully, then return true if sucess, return false if it isnt example

public static bool UpdateTiger(Tiger p)
{
    var command = new SqlCommand();
    command.CommandText = "UPDATE Owner SET Tiger1=@tiger1 WHERE Personnummer=@perNum";

    command.Parameters.AddWithValue("@tiger1", p.tiger1).Direction = ParameterDirection.Input;
    command.Parameters.AddWithValue("@pernum", p.pernum).Direction = ParameterDirection.Input;

    try
    {
        SqlHelper.ExecuteNonQuery(command); // this is where I run the procedure
        return true;
    }
    catch (Exception e)
    {

        return false;
    }

then create another method for other kinds of updates

Answer 2

I found the problem. I had forgotten to update my array before sending it in to the code :). Thanks for your time!

Answer 3

Is persNo an int being passed as a string? If it is an actual string, you might want to check the query. If a string, your query would look like this: ...WHERE Personnummer=someString when you would really want ...WHERE Personnummer='someString' . If that is not it, try putting a break in the code in Visual Studio on the line after cmd is set or Debug.Print(cmd.CommandText); somewhere after it is set to see what the query is that is being executed. Given there is no error, I would say your WHERE condition is not providing a match to update anything in the database.