SQL 2008 MSDN seminar

Just got back from a SQL 2008 MSDN UK seminar at Thames Valley Park (TVP). I was a fairly simple set of presentations to give a quick flavour of what 2008 may mean for developers. So here is an even quicker flavour…
Data Types: Some new data types including lots of date/time types (probably the ones that were in the 2005 CTPs), File Stream (for files that are actually stored on disk) but the most interesting one was the Hierarchy Id. This allows the developer to construct real hierarchy relationships and ask questions such as who is the ancestor of x. However it does need to be manipulated via a whole set of related functions. The seminar also spent far too long on spatial types, ok map data is all the rage but who cares about this? Ever since SQL 2005 I’ve been worried about the potential explosion of CLR types in the database, and this just seems to meet my worst fears. I think you can smell a CLR type because of the extra functions, I really wonder how well (or not) they’ll perform.

Semi-Structured data: Interesting change, where you can add sparse columns to a table. The idea is that you can create many columns (wide table) to cover many attributes without overloading the table. This could be useful for storing derived types in the database. The classic example would be Animal classification. Not every animal has the same attributes but you can put the whole range in the table schema when in reality only a few will be used on any one row. I’m not sure how the Codd brigade will take to this!

Filtered Index: Didn’t really cover this but it seems that you can create an index that only includes data that meets a criteria. For example you could create a dog index for the animal table that would only contain data that matches the "dog" value.

Integration Services: The use of parallel execution and the inclusion of ADO.NET sources.

Tracking Changes: Oh yes this stuff could be great, but will it perform well? Two types; Change Tracking – aimed at synchronisation activities, conflict resolution, etc. Change Data Capture – aimed at replaying changes to a different database.

Merge: This looked very powerful, the ability to use one statement to merge data from one table to another. This seems to avoid the age old SQL problem of knowing if you need to insert a new row or update and existing one, with Merge you can do it all with one statement. Looks suspiciously like an XQuery to me, again the spectre of performance rises.

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