SQL Server 2008 Books Online Update (January 2009)

The January 2009 update of SQL Server 2008 Books Online has been released last Friday. The installation file is available for download:

• Microsoft SQL Server 2008 Books Online (January 2009).

An update of the sample databases is scheduled for spring, and by the looks of things that's still very far away. ;)

Anyway, the samples are available at CodePlex:

• SQL Server 2008 SR1 – stable release, October 31^st 2008;
• [SQL Server 2008 SR2] – alpha, proceed with caution.

Now, go back to work! – he said to himself.

ML

2008 May Not Be the Last for Planet Earth

What do you think?

Have a good one!

ML

Sparse Columns and Filtered Indexes

At the December meeting of SLODUG, the Slovenian Developers User Group, I've presented two new functionalities introduced with SQL Server 2008:

• Sparse Columns – a new (or, at least, an improved) way of storing data in nillable columns so that non-existent data takes up virtually no space in the database.
  
  Well, to be honest, storage usage *is* affected (as the maximum size of a row in a table is decreased from 8,060 Bytes to 8,018 Bytes) but with this change the maximum number of columns in a table is increased to 30,000 (including a former maximum of 1,024 non-sparse columns).
  
  With the introduction of sparse columns SQL Server 2008 recognizes two types of tables: wide tables (containing at least one sparse column) and non-wide tables (containing no sparse columns, only "regular" ones – nillable or not);
• Filtered Indexes – by introducing the WHERE clause to the definition of indexes (and statistics) on base tables restrictions can be applied to data sets being indexed, thus introducing several new possibilities, such as:
  
  – sparse keys (nillable/sparse columns can now be used as keys);
  
  – conditional constraints (unique constraints can be created on subsets of data); and
  
  – this also extends the usability of covering indexes (by indexing one or more subsets of data one could effectively partition data without having to use Table Partitioning).

More on these two subjects (and why they actually represent the same one) is available in the presentation. Clue: Rational Flexibility.

(Or rather the files *will be* available as soon as they've been uploaded to the SLODUG site.)

Stay tuned...

ML