急`求高手帮忙写下C#代码注释 万分感激 明天要答辩...PART5

明天就要答辩了，程序不是我自己做的希望高手给我翻译下代码的含义，
以下代码是请假模块的BLL方法部分代码 希望高手可以逐行解释下 我上台就照你的说！！！
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public Leave getMessage(int leaveid)
{
string str = "select typeid,reason,denyreason from tblleave where leaveid=@leaveid";
Database db = DatabaseFactory.CreateDatabase("OASystemDSN");
DbCommand dbCommand = db.GetSqlStringCommand(str);
db.AddInParameter(dbCommand,"leaveid",DbType.Int32,leaveid);
using (IDataReader dr = db.ExecuteReader(dbCommand))
{
while (dr.Read())
{
aleave.TypeId = Convert.ToInt32(dr["typeid"].ToString());
aleave.Reason = dr["reason"].ToString();
aleave.DenyReason=dr["denyreason"].ToString ();