getting db connection through singleton class

Question

I have created an singleton class, this class returns a database connection. So my question is this connection is also satisfying singleton criteria?
If no, than how I c

Answer 1

The connection itself is not satisfying the Singleton criteria because you can create multiple instances of a database connection object. A singleton by definition can only be instantiated once.

You can make the SqlConnection a part of the Singleton, by changing your example to this:

public sealed class SingletonDB
{
    private static readonly SingletonDB instance = new SingletonDB();
    private readonly SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["mydb"].ConnectionString);

    // Explicit static constructor to tell C# compiler
    // not to mark type as beforefieldinit
    static SingletonDB()
    {
    }

    private SingletonDB()
    {
    }

    public static SingletonDB Instance
    {
        get
        {
            return instance;
        }
    }

    public SqlConnection GetDBConnection()
    {
        return con;
    }
}

This way the SqlConnection used by your SingletonDB class would have one and only one SqlConnection, thus follow the Singleton pattern.