How to use multiple connections to connect to existing database in memory mode in 0.7.1?

[yxmm-wxe]

In the latest code, I found the commit Isolate multiple in-memory database from each other.

So when I get an in-memory connection every time, it will be connected to a new database.

How to use multiple connections to connect to the existing database in memory mode? Any plans to expand this functionality?

[Giorgi]

@yxmm-wxe SQLite supports sharing in-memory databases between connections: In-Memory Databases but I don't see anything like that in DuckDB docs. I asked in DuckDB Discord, let's see what answer I get.

[Giorgi]

JDBC supports it because JDBC driver is built by the core DuckDB team while this project is built mostly by only me in my spare time. As I said already I can't promise that I will do it in near future.

[yxmm-wxe]

Got it. Thanks for your contribution. I am also willing to try to contribute this functionality in my spare time.

[yxmm-wxe]

@Giorgi I am very sorry to ask a low-level question.

I'd like to build and run a test in VS on Windows. The command dotnet build -c Debug /p:BuildType=Full is executed. But when I run a test in VS, it always prompts the following error. While it does have duckdb.dll in DuckDB.NET\bin\Debug\net6.0\runtimes\win-x64 and DuckDB.NET\obj\runtimes\win-x64\native.

System.DllNotFoundException : Unable to load DLL 'duckdb' or one of its dependencies: The specified module could not be found. (0x8007007E)

Are there any missing steps?

[Giorgi]

Are you running tests in Debug mode? There is ModuleInit class the loads duckdb before running tests. Try putting a breakpoint there and debugging tests to see where it is looking for the duckdb.dll.

[yxmm-wxe]

Thanks! It works.

[Giorgi]

I created a new issue to track this functionality: Support shared in-memory databases

[yxmm-wxe]

Already implemented in #88.

It can use the connection string DataSource=:memory:?cache=shared to get and use the shared in-memory database.

It can also use the connection string DataSource=:memory: to get and use an isolated in-memory database and use connection.Duplicate() to get another connection for the existing isolated in-memory database.