Explicit GC.gc() needed for SQLite.DB to become really out of scope.

[MarieJC]

Otherwise at the end of program execution sqlite database remains in use by Julia REPL.
And according to the doc: "The SQLite.DB will be automatically closed/shutdown when it goes out of scope (i.e. the end of the Julia session, end of a function call wherein it was created, etc" - turns out not true!
Link to JuliaLang discussion of the problem:
https://discourse.julialang.org/t/sqlite-database-remains-in-use-by-julia-repl/77194

[quinnj]

Hi @MarieJC, thanks for opening an issue! Yeah, this is somewhat a general Julia "destructor" problem as we're relying on the finalizer functionality in Julia, which allows you to register a function that runs when an object is garbage collected. But the problem is, as you noted, it's not well-defined when objects actually get garbage-collected!

Do note that you can always call close(db) or more generally DBInterface.close!(db) to force a database connection to be closed, which we should probably highlight in the docs as the proper way to manage the lifetime resource of your sqlite database connection.

[MarieJC]

Thank you for your response! Yes, DBInterface.close!(db) works. But in my particular exercise the code operating on a db isspread between diff functions - so it is tricky to close the db at the very end. This is not a priority though!!! We were just testing out similar functionality in several languages, including Julia.