Sql Server: Compact and LocalDB Denali

Question

Does anyone knows the differences between these ones?

1. http://www.microsoft.com/sqlserver/en/us/editions/express.aspx (Look for CTP3 LocalDB in the page)
2. http://www.microsoft.com/sqlserver/en/us/editions/compact.aspx

I wonder why microsoft started Denali project (now in CTP).

Answer 1

I got my answer here:

LocalDB and SQL Server Compact?

Small and simple database, lightweight installation, connecting to a database file -- this will sound familiar to any developer using SQL Server Compact. The similarities are not accidental, as our goal for LocalDB was to be as easy to use as SQL Server Compact (while being as powerful and compatible with full SQL Server as SQL Express).

There are significant differences between LocalDB and SQL Server Compact:

Execution mode: SQL Server Compact is an in-proc DLL, while LocalDB runs as a separate process.

Disk usage: all SQL Server Compact binaries amount to some 4MBs, while LocalDB installation takes 140MBs.

Features: SQL Server Compact offers core RDBMS functionality like querying, while LocalDB provides a much richer set of features, including Stored Procedures, Geometry and Geography data types, etc.

Answer 2

A comparision between the different features of CE3.5, CE4, 2008 R2 Express and LocalDB (Denali CTP3) can be found here

http://erikej.blogspot.com/2011/01/comparison-of-sql-server-compact-4-and.html

(yes a link - because it 's still a CTP)