Question

I’ve been using the below sample code snippet to update a SQL Server 2005 database table. It converts a List<T> where T is a custom object with a series of properties (fields) into XML attributes on row elements nested inside a row root element.

In this way, I make a huge series of inserts in one SQL transaction. Following this similar route, I wanted to provide an XML series of updates rather than inserts. I wasn’t able to find any good sources on how I might adapt this approach for that. e.g. Say update B thru F based on a primary key A.

conn.Open();
cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = @"INSERT table (A,B,C,D,E,F) 
SELECT Tbl.Col.value('@A','nvarchar(50)'),
       Tbl.Col.value('@B','int'),
       Tbl.Col.value('@C','nvarchar(50)'),
       Tbl.Col.value('@D','nvarchar(1000)'),
       Tbl.Col.value('@E','nvarchar(50)'),
       Tbl.Col.value('@F','nvarchar(50)')
FROM @xml.nodes('//row') Tbl(Col)";
cmd.Parameters.Add("@xml", SqlDbType.Xml).Value = new XDocument(
new XDeclaration("1.0", "utf-8", "yes"),
new XElement("rows",
toInsert.Select(p => new XElement("row", new XAttribute("A", x.Prop1),
                     new XAttribute("B", x.Prop2),
                     new XAttribute("C", x.Prop3),
                     new XAttribute("D", x.Prop4),
                     new XAttribute("E", x.Prop5),
                     new XAttribute("F", x.Prop6))))).ToString();
Console.WriteLine(cmd.ExecuteNonQuery().ToString() + " row(s) affected.");
conn.Close();

Answer 1

If you want to stick with this method you can modify the insert and perform the update instead using the following sql:

update  yourTable 
        set b = Tbl.Col.value('@B','int')
        --other cols...
from     yourTable y
join    @xml.nodes('//row') Tbl(Col) on
        y.a = Tbl.Col.value('@A','nvarchar(50)')