updating posts in a Database

[cyrus71]

hi,

it is my problem:

I fetch rss feeds from web and insert them into my table, and i do it every ten minuts.
every time i must check

1- if the item already exists in my table if it exists then i must chech the publishdate if the publishdate has changed then the item must be updated. if the item exists and publishdate not changed so i have to chech if it is more than 20 days old, i must delete it if it is more than 20 days old otherwise no changing.

2- if the item not exists i have to insert it into table.

here is my code that checks SOME of my conditions but it inserts all items every time i fetch them.
i need some code.

//i load the items in xmldocument first and select all my items in the table and then i compare them one by one.

xmlNodeList = XmlDoc.SelectNodes("rss/channel/item");
DataSet DS = new DataSet();
DS = RSSFWS.GetItems(ChannelId);

if (DS.Tables["items"].Rows.Count > 0)
{
DataRow DR;
for (int i = 0; i < xmlNodeList.Count; i++)
{
xmlNode = xmlNodeList;
for (int j = 0; j < DS.Tables["items"].Rows.Count; j++)
{
DR = DS.Tables["items"].Rows[j];
if(DR["title"].ToString() != xmlNode["title"].InnerText)
{
if (j == DS.Tables["items"].Rows.Count)
{
AddItem(xmlNode, ChannelId); //here it should insert it if the item does not exist but it insert all of them.
}
}
}
}
}