rusqlite/libsqlite3-sys

Rusqlite

Rusqlite is an ergonomic wrapper for using SQLite from Rust.

Historically, the API was based on the one from rust-postgres. However, the two have diverged in many ways, and no compatibility between the two is intended.

Usage

In your Cargo.toml:

[dependencies]
# `bundled` causes us to automatically compile and link in an up to date
# version of SQLite for you. This avoids many common build issues, and
# avoids depending on the version of SQLite on the users system (or your
# system), which may be old or missing. It's the right choice for most
# programs that control their own SQLite databases.
#
# That said, it's not ideal for all scenarios and in particular, generic
# libraries built around `rusqlite` should probably not enable it, which
# is why it is not a default feature -- it could become hard to disable.
rusqlite = { version = "0.27.0", features = ["bundled"] }

Simple example usage:

use rusqlite::{Connection, Result};

#[derive(Debug)]
struct Person {
    id: i32,
    name: String,
    data: Option<Vec<u8>>,
}

fn main() -> Result<()> {
    let conn = Connection::open_in_memory()?;

    conn.execute(
        "CREATE TABLE person (
            id    INTEGER PRIMARY KEY,
            name  TEXT NOT NULL,
            data  BLOB
        )",
        (), // empty list of parameters.
    )?;
    let me = Person {
        id: 0,
        name: "Steven".to_string(),
        data: None,
    };
    conn.execute(
        "INSERT INTO person (name, data) VALUES (?1, ?2)",
        (&me.name, &me.data),
    )?;

    let mut stmt = conn.prepare("SELECT id, name, data FROM person")?;
    let person_iter = stmt.query_map([], |row| {
        Ok(Person {
            id: row.get(0)?,
            name: row.get(1)?,
            data: row.get(2)?,
        })
    })?;

    for person in person_iter {
        println!("Found person {:?}", person.unwrap());
    }
    Ok(())
}

Supported SQLite Versions

The base rusqlite package supports SQLite version 3.6.8 or newer. If you need support for older versions, please file an issue. Some cargo features require a newer SQLite version; see details below.

Optional Features

Rusqlite provides several features that are behind Cargo features. They are:

• load_extension allows loading dynamic library-based SQLite extensions.
• backup allows use of SQLite's online backup API. Note: This feature requires SQLite 3.6.11 or later.
• functions allows you to load Rust closures into SQLite connections for use in queries. Note: This feature requires SQLite 3.7.3 or later.
• window for window function support (fun(...) OVER ...). (Implies functions.)
• trace allows hooks into SQLite's tracing and profiling APIs. Note: This feature requires SQLite 3.6.23 or later.
• blob gives std::io::{Read, Write, Seek} access to SQL BLOBs. Note: This feature requires SQLite 3.7.4 or later.
• limits allows you to set and retrieve SQLite's per connection limits.
• chrono implements FromSql and ToSql for various types from the chrono crate.
• serde_json implements FromSql and ToSql for the Value type from the serde_json crate.
• time implements FromSql and ToSql for the time::OffsetDateTime type from the time crate.
• url implements FromSql and ToSql for the Url type from the url crate.
• bundled uses a bundled version of SQLite. This is a good option for cases where linking to SQLite is complicated, such as Windows.
• sqlcipher looks for the SQLCipher library to link against instead of SQLite. This feature overrides bundled.
• bundled-sqlcipher uses a bundled version of SQLCipher. This searches for and links against a system-installed crypto library to provide the crypto implementation.
• bundled-sqlcipher-vendored-openssl allows using bundled-sqlcipher with a vendored version of OpenSSL (via the openssl-sys crate) as the crypto provider.
  • As the name implies this depends on the bundled-sqlcipher feature, and automatically turns it on.
  • If turned on, this uses the openssl-sys crate, with the vendored feature enabled in order to build and bundle the OpenSSL crypto library.
• hooks for Commit, Rollback and Data Change notification callbacks.
• unlock_notify for Unlock notification.
• vtab for virtual table support (allows you to write virtual table implementations in Rust). Currently, only read-only virtual tables are supported.
• series exposes generate_series(...) Table-Valued Function. (Implies vtab.)
• csvtab, CSV virtual table written in Rust. (Implies vtab.)
• array, The rarray() Table-Valued Function. (Implies vtab.)
• i128_blob allows storing values of type i128 type in SQLite databases. Internally, the data is stored as a 16 byte big-endian blob, with the most significant bit flipped, which allows ordering and comparison between different blobs storing i128s to work as expected.
• uuid allows storing and retrieving Uuid values from the uuid crate using blobs.
• session, Session module extension. Requires buildtime_bindgen feature. (Implies hooks.)
• extra_check fail when a query passed to execute is readonly or has a column count > 0.
• column_decltype provides columns() method for Statements and Rows; omit if linking to a version of SQLite/SQLCipher compiled with -DSQLITE_OMIT_DECLTYPE.
• collation exposes sqlite3_create_collation_v2.

Notes on building rusqlite and libsqlite3-sys

libsqlite3-sys is a separate crate from rusqlite that provides the Rust declarations for SQLite's C API. By default, libsqlite3-sys attempts to find a SQLite library that already exists on your system using pkg-config, or a Vcpkg installation for MSVC ABI builds.

You can adjust this behavior in a number of ways:

• If you use the bundled, bundled-sqlcipher, or bundled-sqlcipher-vendored-openssl features, libsqlite3-sys will use the cc crate to compile SQLite or SQLCipher from source and link against that. This source is embedded in the libsqlite3-sys crate and is currently SQLite 3.38.0 (as of rusqlite 0.27.0 / libsqlite3-sys 0.24.0). This is probably the simplest solution to any build problems. You can enable this by adding the following in your Cargo.toml file:

  [dependencies.rusqlite]
  version = "0.27.0"
  features = ["bundled"]
  

• When using any of the bundled features, the build script will honor SQLITE_MAX_VARIABLE_NUMBER and SQLITE_MAX_EXPR_DEPTH variables. It will also honor a LIBSQLITE_FLAGS variable, which can have a format like "-USQLITE_ALPHA -DSQLITE_BETA SQLITE_GAMMA ...". That would disable the SQLITE_ALPHA flag, and set the SQLITE_BETA and SQLITE_GAMMA flags. (The initial -D can be omitted, as on the last one.)

• When using bundled-sqlcipher (and not also using bundled-sqlcipher-vendored-openssl), libsqlite3-sys will need to link against crypto libraries on the system. If the build script can find a libcrypto from OpenSSL or LibreSSL (it will consult OPENSSL_LIB_DIR/OPENSSL_INCLUDE_DIR and OPENSSL_DIR environment variables), it will use that. If building on and for Macs, and none of those variables are set, it will use the system's SecurityFramework instead.

• When linking against a SQLite (or SQLCipher) library already on the system (so not using any of the bundled features), you can set the SQLITE3_LIB_DIR (or SQLCIPHER_LIB_DIR) environment variable to point to a directory containing the library. You can also set the SQLITE3_INCLUDE_DIR (or SQLCIPHER_INCLUDE_DIR) variable to point to the directory containing sqlite3.h.

• Installing the sqlite3 development packages will usually be all that is required, but the build helpers for pkg-config and vcpkg have some additional configuration options. The default when using vcpkg is to dynamically link, which must be enabled by setting VCPKGRS_DYNAMIC=1 environment variable before build. vcpkg install sqlite3:x64-windows will install the required library.

• When linking against a SQLite (or SQLCipher) library already on the system, you can set the SQLITE3_STATIC (or SQLCIPHER_STATIC) environment variable to 1 to request that the library be statically instead of dynamically linked.

Binding generation

We use bindgen to generate the Rust declarations from SQLite's C header file. bindgen recommends running this as part of the build process of libraries that used this. We tried this briefly (rusqlite 0.10.0, specifically), but it had some annoyances:

• The build time for libsqlite3-sys (and therefore rusqlite) increased dramatically.
• Running bindgen requires a relatively-recent version of Clang, which many systems do not have installed by default.
• Running bindgen also requires the SQLite header file to be present.

As of rusqlite 0.10.1, we avoid running bindgen at build-time by shipping pregenerated bindings for several versions of SQLite. When compiling rusqlite, we use your selected Cargo features to pick the bindings for the minimum SQLite version that supports your chosen features. If you are using libsqlite3-sys directly, you can use the same features to choose which pregenerated bindings are chosen:

• min_sqlite_version_3_6_8 - SQLite 3.6.8 bindings (this is the default)
• min_sqlite_version_3_6_23 - SQLite 3.6.23 bindings
• min_sqlite_version_3_7_7 - SQLite 3.7.7 bindings

If you use any of the bundled features, you will get pregenerated bindings for the bundled version of SQLite/SQLCipher. If you need other specific pregenerated binding versions, please file an issue. If you want to run bindgen at buildtime to produce your own bindings, use the buildtime_bindgen Cargo feature.

If you enable the modern_sqlite feature, we'll use the bindings we would have included with the bundled build. You generally should have buildtime_bindgen enabled if you turn this on, as otherwise you'll need to keep the version of SQLite you link with in sync with what rusqlite would have bundled, (usually the most recent release of SQLite). Failing to do this will cause a runtime error.

Contributing

Rusqlite has many features, and many of them impact the build configuration in incompatible ways. This is unfortunate, and makes testing changes hard.

To help here: you generally should ensure that you run tests/lint for --features bundled, and --features "bundled-full session buildtime_bindgen".

If running bindgen is problematic for you, --features bundled-full enables bundled and all features which don't require binding generation, and can be used instead.

Checklist

• Run cargo fmt to ensure your Rust code is correctly formatted.
• Ensure cargo clippy --workspace --features bundled passes without warnings.
• Ensure cargo clippy --workspace --features "bundled-full session buildtime_bindgen" passes without warnings.
• Ensure cargo test --workspace --features bundled reports no failures.
• Ensure cargo test --workspace --features "bundled-full session buildtime_bindgen" reports no failures.

Author

Rusqlite is the product of hard work by a number of people. A list is available here: https://github.com/rusqlite/rusqlite/graphs/contributors

Community

Feel free to join the Rusqlite Discord Server to discuss or get help with rusqlite or libsqlite3-sys.

License

Rusqlite and libsqlite3-sys are available under the MIT license. See the LICENSE file for more info.

Licenses of Bundled Software

Depending on the set of enabled cargo features, rusqlite and libsqlite3-sys will also bundle other libraries, which have their own licensing terms:

• If --features=bundled-sqlcipher is enabled, the vendored source of SQLcipher will be compiled and statically linked in. SQLcipher is distributed under a BSD-style license, as described here.

• If --features=bundled is enabled, the vendored source of SQLite will be compiled and linked in. SQLite is in the public domain, as described here.

Both of these are quite permissive, have no bearing on the license of the code in rusqlite or libsqlite3-sys themselves, and can be entirely ignored if you do not use the feature in question.