I'm using this code:

public void InsertMember(Member member)
{
    string INSERT = "INSERT INTO Members (Name, Surname, EntryDate) VALUES (@Name, @Surname, @EntryDate)";

    using (sqlConnection = new SqlConnection(sqlConnectionString_WORK))
    {
        sqlConnection.Open();

        using (SqlCommand sqlCommand = new SqlCommand(INSERT, sqlConnection))
        {
            sqlCommand.Parameters.Add("@Name", SqlDbType.VarChar).Value = member.Name;
            sqlCommand.Parameters.Add("@Surname", SqlDbType.VarChar).Value = member.Surname;
            sqlCommand.Parameters.Add("@EntryDate", SqlDbType.Date).Value = member.EntryDate;

            sqlCommand.ExecuteNonQuery();
        }
    }
}

It's not showing any errors or problems at all. Is it wrong if I don't add sqlConnection.Close(); before disposing of it? If yes, why?