I just installed SQL Server Express 2008 because of intellisense feature. It worked at first but than it stopped working. Looking for the option to check and later consulting Google I have found that it looks like Microsoft disabled intellisense if you connect to SQL Server 2005 databases.
Is this absolutely correct ?
Is there any solution for this (some registry "switch") ?
If you'd like to see the feature added, vote for the request on Connect. Here is feedback from the team regarding why it was dropped:
Let me share product team’s information about the version support of IntelliSense. This was a truly by-design from the beginning of IntelliSense project and it was a part of business decision. Implementation of IntelliSense requires a full fidelity of engine parser reconstruction in client side using managed code base. Support of multiple server versions means design and implementation of multiple versions of parsers and related infra in parallel. This multiplies time and cost to develop, test and support. At the same time, the core module is an important product base that enables not only IntelliSense feature but also other products including Upgrade Advisor to analyze scripts; in the long term, it is potentially any feature that needs syntactic and semantic understanding of Transact-SQL language.
In CTP5 and CTP6, IntelliSense had a known issue that it did not correctly check the server version so CTP users could connect any version of SQL Server with IntelliSense. While some users didn't notice it, IntelliSense was not correctly working as desired. The impact was that IntelliSense had a high potential to guide users to script incorrect Transact-SQL or to false-negatively indicate that a script has errors while it is perfectly valid in those versions.
Considering the number one goal of IntelliSense is to increase productivity of authoring complex query or stored procedure (or simply Transact-SQL scripts), this issue was regarded as a factor to decrease productivity which is a huge negative impact from a new feature.
In RC0, this known issue was corrected that IntelliSense checks the server version and provides its feature on supported version which is SQL Server 2008.
As a version one, IntelliSense is enabled on a subset of Transact-SQL language. It is because the large scope of work to implement lexer, parser, binder and script document object model in managed code for entire language scope. The product team is moving forward with a focus on expanding the language support scope.
I hope this information provides the background information at minimum why the target version was selected on SQL Server 2008 only.
Anyone using the RTM build should consider the CU1 (Cumulative Update 1) build available here as quite a few IntelliSense bugs were addressed.