Is there a difference between SQL Server Express (2012) and LocalDB?

Question

In its excellent and popular comparison chart, ErikEJ distinguishes between SQL Server Express 2012 and SQL Server 2012 LocalDB . However, I cannot find such a difference anywhere in the MSDN documentation ("LocalDB" is not even mentioned in the official MS SS12 book or on the MSDN SQL Edition comparison page .) This makes me think that Express and LocalDB are actually not two separate products as ErikEJ suggests, but two different terms for the same thing (which explains why it is called "SQL Server 2012 Express LocalDB " on this MSDN page ).

If there really is a difference between the products, can someone point me to the official documentation comparing them?

Answer 1

OK, I think I found the answer to my question. (He was buried under the tabs on the SS Express product page .)

Here is a summary of the distinctive features of LocalDB that I found on this page:

• LocalDB is a lightweight deployment option for SQL Server Express Edition with fewer prerequisites and faster installation.
• LocalDB has all the same programming features as SQL Express, but works in "user mode" * with applications, and not as a service.
• LocalDB is not intended for multi-user scripts or for use as a server. (If you need to accept remote connections or administer remotely, you need SQL Server Express.)
• Express with Tools (which includes SS Management Studio Express, Azure, etc.) Can be used with or without LocalDB. (The same goes for Express with Advanced Services.)

UPDATE: I just found this useful description on Windows IT Pro (Jul '12, p. 23) :

LocalDB is not SQL Server Express and is not SQL Server Compact. LocalDB uses the same sqlservr.exe mechanism as other editions of SQL Server, but operates in user mode and not as a service. LocalDB is used for offline development by tools such as SSDT to ensure 100% compatibility of the code you are developing with your SQL Server production database.

If I read correctly, LocalDB is more like an Express configuration option than a standalone product. Therefore, obviously, if I download Express (or Express with tools), I will have the opportunity to install a version of LocalDB that is supposedly simpler ("zero configuration") than the full version of Express. (Update: With VS2012, LocalDB is installed by default .)

According to this post , another important difference is that "Visual Studio 2010 is not really working with LocalDB at this time." (Instead, we should use SS Management Studio, at least for now.)

* (The concept of "User Mode" or "User Instances" is a key difference between LocalDB. In fact, according to this post , "LocalDB can be seen as updating the function of user instances of SQL Server Express." For user instances, see the MSDN blog . What is RANU? " )

Answer 2

I use a table from ErikEJ that shows: features and differences between SQL CE 3.5, SQL CE 4, Local DB, and SQL Server 2012 . According to this table, the differences between Local DB and SQL Server 2012:

Installation Size:
SQL Server 2012: 120 MB download size 300 MB expanded to disk
Local DB: 32 MB; 160 MB on disk

Works as a service
SQL Server 2012: Yes
Local DB: None (runs as a process launched by the application)

FILESTREAM Support
SQL Server 2012: Yes
Local DB: No

Merge Replication Subscriber
SQL Server 2012: Yes
Local DB: No

Number of Parallel Connections
SQL Server 2012: Unlimited Local Database: Unlimited (but only locally)

NB: Sorry, this is not an “official documentation”, but I hope this is useful for the next module, as it answers the basic request for differences.

Answer 3

The main difference between Server Express runs as a service, and LocalDB does not require any server or intensive processing.