When playing with our MCP server with Claude Code, I realized that
having the agent pre-configured to a specific path is just not very
useful.
I am now adding two new commands, to open a database and to list
the current database. Those make our server more useful.
This is just the bare minimum that I needed to convince myself that this
approach will work. The only views that we support are slices of the
main table: no aggregations, no joins, no projections.
drop view is implemented.
view population is implemented.
deletes, inserts and updates are implemented.
much like indexes before, a flag must be passed to enable views.
We should be allocator-agnostic. It is pretty limiting for us to force a
user to use a particular allocator. This is specially restricting for
`no_std` in the future.
Reviewed-by: bit-aloo (@Shourya742)
Reviewed-by: Preston Thorpe <preston@turso.tech>
Closes#2481
Support for attaching databases. The main difference from SQLite is that
we support an arbitrary number of attached databases, and we are not
bound to just 100ish.
We for now only support read-only databases. We open them as read-only,
but also, to keep things simple, we don't patch any of the insert
machinery to resolve foreign tables. So if an insert is tried on an
attached database, it will just fail with a "no such table" error - this
is perfect for now.
The code in core/translate/attach.rs is written by Claude, who also
played a key part in the boilerplate for stuff like the .databases
command and extending the pragma database_list, and also aided me in
the test cases.
There's no such thing as a read-only connection.
In a normal connection, you can have many attached databases. Some
r/o, some r/w.
To properly fix that, we also need to fix the OpenWrite opcode. Right
now we are passing a name, which is the name of the table. That
parameter is not used anywhere. That is also not what the SQLite opcode
specifies. Same as OpenRead, the p3 register should be the database
index.
With that change, we can - for now - pass the index 0, which is all
we support anyway, and then use that to test if we are r/o.
Closes#2121
There are two important things to point out:
1. The support is incomplete since we yet don't support savepoints in
core.
2. When a txn drops we should call `_finish()` on it, but since async
drop is [unstable](https://github.com/rust-lang/rust/issues/126482) the
best solution that I came up was just forcing the user to explicitly
call `finish()` before any drops.
Closes#2151
I ended up hitting #1974 today and wanted to fix it. I worked with
Claude to generate a more comprehensive set of queries that could fail
aside from just the insert query described in the issue. He got most of
them right - lots of cases were indeed failing. The ones that were
gibberish, he told me I was absolutely right for pointing out they were
bad.
But alas. With the test cases generated, we can work on fixing it. The
place where the assertion was hit, all we need to do there is return
true (but we assert that this is indeed a string literal, it shouldn't
be anything else at this point).
There are then just a couple of places where we need to make sure we
handle double quotes correctly. We already tested for single quotes in a
couple of places, but never for double quotes.
There is one funny corner case where you can just select "col" from tbl,
and if there is no column "col" on the table, that is treated as a
string literal. We handle that too.
Fixes#1974Closes#2152
Currently ignored. The reason we are adding it is so that we have
an output that can fit in a single line. This is so we can use it in
tests, and have a predictable output pattern for both sqlite and turso.
The SQLite command line has facilities to ingest things like csv, and
other formats. But here we are, in 2025, and I asked Claude if Turso's
CLI should, in the same vein, have a native MCP server.
Claude told me: "You're absolutely right!" "That's a great insight!"
"That's a fantastic idea!" and then proceeded to help me with the
boilerplate for this beautiful server.
Rust has a crate, mcp_server, that implements an mcp_server trait.
However, that depends on Tokio, and I think that would bloat our binary
too much.
I have also considered implementing an MCP server that operates on a
directory and allows to list many SQLite files, but figured that would
be a good job for a more advanced and specialized server, not for the
one that comes by default with the CLI. Let's go for simple.
