Database diagram support objects cannot be installed...

Twice is two weeks SQL 2005 has reported the following error when I've clicked on the database diagrams node on certain databases;

"Database diagram support objects cannot be installed because this database does not have a valid owner".

The databases in question were restored onto my local SQL from backups on other machines and servers. I'd restore the database, set the owner using ALTER AUTHORIZATION, and then try to create a database diagram, only to be presented with the above error.

The symptoms actually mask the underlying problem - the database's compatibility mode. On both occasions the compatibility level was set to SQL 2000 (80) for the restored databases and it should be set to SQL 2005 (90). To resolve;

• Open the properties for the affected database
• Go to the options section
• Change the compatibility level to SQL 2005 (90)

Introducing LINQ (to objects) in 10 seconds

The database uses of LINQ (to SQL/to Entities) get all of the glory, but LINQ can be used against your run of the mill objects in .NET. Take for example sorting strings;

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static void Main(string[] args) {   string[] friends = new string[]{     "Tony Johnson",     "Joe Mangel",     "Helen Daniels",     "Sky Mangel",     "Stingray",     "Dylan Timmins",     "Gerard Rebbeci",     "Pippa Styger"};   IEnumerable<string> sorted = from friend in friends orderby friend select friend;   foreach (string person in sorted)     Console.WriteLine(person); }

The interesting part is on lines 13/14 - we get a list of sorted strings by executing SQL like syntax on our string array. Lets try something else, lets sort the list based on who's got the longest name, sorting from longest to shortest: Notice I'm also using anonymous types in the following example( var ).

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static void Main(string[] args) {   var friends = new string[]{     "Tony Johnson",     "Joe Mangel",     "Helen Daniels",     "Sky Mangel",     "Stingray",     "Dylan Timmins",     "Gerard Rebbeci",     "Pippa Styger"};   var sorted = from friend in friends          orderby friend.Length descending          select friend;   foreach (var person in sorted)     System.Console.WriteLine(person); }

Easy, but very useful. You can use LINQ to sort collections of objects and do all sorts of powerful and useful things.