Npgsql.Tests.CommandTests.PreparedStatementWithParameters C# (CSharp) Method

        public void PreparedStatementWithParameters()
        {
            using (var conn = OpenConnection())
            {
                conn.ExecuteNonQuery("CREATE TEMP TABLE data (int INTEGER, long BIGINT)");
                using (var command = new NpgsqlCommand("select * from data where int = :a and long = :b;", conn))
                {
                    command.Parameters.Add(new NpgsqlParameter("a", DbType.Int32));
                    command.Parameters.Add(new NpgsqlParameter("b", DbType.Int64));
                    Assert.AreEqual(2, command.Parameters.Count);
                    Assert.AreEqual(DbType.Int32, command.Parameters[0].DbType);

                    command.Prepare();
                    command.Parameters[0].Value = 3;
                    command.Parameters[1].Value = 5;
                    using (var dr = command.ExecuteReader())
                    {
                        Assert.IsNotNull(dr);
                    }
                }
            }
        }