ISAR/rusqlite
3
0
Fork 0
mirror of https://github.com/isar/rusqlite.git synced 2024-10-23 06:51:08 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add documentation

Browse Source
This commit is contained in:
John Gallagher 2014-11-03 17:11:00 -05:00
parent 949260046c
commit b34f255aac
3 changed files with 386 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

258
src/lib.rs
View File

@ -1,3 +1,52 @@
//! Rusqlite is an ergonomic, semi-safe wrapper for using SQLite from Rust. It attempts to expose
//! an interface similar to [rust-postgres](https://github.com/sfackler/rust-postgres).
//!
//! ```rust
//! extern crate rusqlite;
//! extern crate time;
//!
//! use time::Timespec;
//! use rusqlite::SqliteConnection;
//!
//! #[deriving(Show)]
//! struct Person {
//! id: i32,
//! name: String,
//! time_created: Timespec,
//! data: Option<Vec<u8>>
//! }
//!
//! fn main() {
//! let conn = SqliteConnection::open(":memory:").unwrap();
//!
//! conn.execute("CREATE TABLE person (
//! id INTEGER PRIMARY KEY,
//! name TEXT NOT NULL,
//! time_created TEXT NOT NULL,
//! data BLOB
//! )", []).unwrap();
//! let me = Person {
//! id: 0,
//! name: "Steven".to_string(),
//! time_created: time::get_time(),
//! data: None
//! };
//! conn.execute("INSERT INTO person (name, time_created, data)
//! VALUES ($1, $2, $3)",
//! &[&me.name, &me.time_created, &me.data]).unwrap();
//!
//! let mut stmt = conn.prepare("SELECT id, name, time_created, data FROM person").unwrap();
//! for row in stmt.query([]).unwrap().map(|row| row.unwrap()) {
//! let person = Person {
//! id: row.get(0),
//! name: row.get(1),
//! time_created: row.get(2),
//! data: row.get(3)
//! };
//! println!("Found person {}", person);
//! }
//! }
//! ```
#![feature(globs)]
#![feature(unsafe_destructor)]
#![feature(macro_rules)]
@ -22,8 +71,11 @@ pub use transaction::{SqliteTransactionBehavior,
pub mod types;
mod transaction;
/// Automatically generated FFI bindings (via [bindgen](https://github.com/crabtw/rust-bindgen)).
#[allow(dead_code,non_snake_case,non_camel_case_types)] pub mod ffi;
/// A typedef of the result returned by many methods.
pub type SqliteResult<T> = Result<T, SqliteError>;
unsafe fn errmsg_to_string(errmsg: *const c_char) -> String {
@ -31,9 +83,15 @@ unsafe fn errmsg_to_string(errmsg: *const c_char) -> String {
c_str.as_str().unwrap_or("Invalid error message encoding").to_string()
}
/// Encompasses an error result from a call to the SQLite C API.
#[deriving(Show)]
pub struct SqliteError {
/// The error code returned by a SQLite C API call. See [SQLite Result
/// Codes](http://www.sqlite.org/rescode.html) for details.
pub code: c_int,
/// The error message provided by [sqlite3_errmsg](http://www.sqlite.org/c3ref/errcode.html),
/// if possible, or a generic error message based on `code` otherwise.
pub message: String,
}
@ -48,53 +106,170 @@ impl SqliteError {
}
}
/// A connection to a SQLite database.
///
/// ## Warning
///
/// Note that despite the fact that most `SqliteConnection` methods take an immutable reference to
/// `self`, `SqliteConnection` is NOT threadsafe, and using it from multiple threads may result in
/// runtime panics or data races. The SQLite connection handle has at least two pieces of internal
/// state (the last insertion ID and the last error message) that rusqlite uses, but wrapping these
/// APIs in a safe way from Rust would be too restrictive (for example, you would not be able to
/// prepare multiple statements at the same time).
pub struct SqliteConnection {
db: RefCell<InnerSqliteConnection>,
}
impl SqliteConnection {
/// Open a new connection to a SQLite database.
///
/// Use the special path `:memory:` to create an in-memory database.
/// `SqliteConnection::open(path)` is equivalent to `SqliteConnection::open_with_flags(path,
/// SQLITE_OPEN_READ_WRITE | SQLITE_OPEN_CREATE)`.
pub fn open(path: &str) -> SqliteResult<SqliteConnection> {
let flags = SQLITE_OPEN_READ_WRITE | SQLITE_OPEN_CREATE;
SqliteConnection::open_with_flags(path, flags)
}
/// Open a new connection to a SQLite database.
///
/// Use the special path `:memory:` to create an in-memory database. See [Opening A New
/// Database Connection](http://www.sqlite.org/c3ref/open.html) for a description of valid
/// flag combinations.
pub fn open_with_flags(path: &str, flags: SqliteOpenFlags) -> SqliteResult<SqliteConnection> {
InnerSqliteConnection::open_with_flags(path, flags).map(|db| {
SqliteConnection{ db: RefCell::new(db) }
})
}
/// Begin a new transaction with the default behavior (DEFERRED).
///
/// The transaction defaults to rolling back when it is dropped. If you want the transaction to
/// commit, you must call `commit` or `set_commit`.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// # fn do_queries_part_1(conn: &SqliteConnection) -> SqliteResult<()> { Ok(()) }
/// # fn do_queries_part_2(conn: &SqliteConnection) -> SqliteResult<()> { Ok(()) }
/// fn perform_queries(conn: &SqliteConnection) -> SqliteResult<()> {
/// let tx = try!(conn.transaction());
///
/// try!(do_queries_part_1(conn)); // tx causes rollback if this fails
/// try!(do_queries_part_2(conn)); // tx causes rollback if this fails
///
/// tx.commit()
/// }
/// ```
pub fn transaction<'a>(&'a self) -> SqliteResult<SqliteTransaction<'a>> {
SqliteTransaction::new(self, SqliteTransactionDeferred)
}
/// Begin a new transaction with a specified behavior.
///
/// See `transaction`.
pub fn transaction_with_behavior<'a>(&'a self, behavior: SqliteTransactionBehavior)
-> SqliteResult<SqliteTransaction<'a>> {
SqliteTransaction::new(self, behavior)
}
/// Convenience method to run multiple SQL statements (that cannot take any parameters).
///
/// Uses [sqlite3_exec](http://www.sqlite.org/c3ref/exec.html) under the hood.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn create_tables(conn: &SqliteConnection) -> SqliteResult<()> {
/// conn.execute_batch("BEGIN;
/// CREATE TABLE foo(x INTEGER);
/// CREATE TABLE bar(y TEXT);
/// COMMIT;")
/// }
/// ```
pub fn execute_batch(&self, sql: &str) -> SqliteResult<()> {
self.db.borrow_mut().execute_batch(sql)
}
/// Convenience method to prepare and execute a single SQL statement.
///
/// On success, returns the number of rows that were changed or inserted or deleted (via
/// `sqlite3_changes`).
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection};
/// fn update_rows(conn: &SqliteConnection) {
/// match conn.execute("UPDATE foo SET bar = 'baz' WHERE qux = ?", &[&1i32]) {
/// Ok(updated) => println!("{} rows were updated", updated),
/// Err(err) => println!("update failed: {}", err),
/// }
/// }
/// ```
pub fn execute(&self, sql: &str, params: &[&ToSql]) -> SqliteResult<uint> {
self.prepare(sql).and_then(|mut stmt| stmt.execute(params))
}
/// Get the SQLite rowid of the most recent successful INSERT.
///
/// Uses [sqlite3_last_insert_rowid](https://www.sqlite.org/c3ref/last_insert_rowid.html) under
/// the hood.
pub fn last_insert_rowid(&self) -> i64 {
self.db.borrow_mut().last_insert_rowid()
}
/// Convenience method to execute a query that is expected to return a single row.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection};
/// fn preferred_locale(conn: &SqliteConnection) -> String {
/// conn.query_row("SELECT value FROM preferences WHERE name='locale'", [], |row| {
/// row.get(0)
/// })
/// }
/// ```
///
/// ## Failure
///
/// Panics if:
///
/// * Preparing the query fails.
/// * Running the query fails (i.e., calling `query` on the prepared statement).
/// * The query does not successfully return at least one row.
///
/// If the query returns more than one row, all rows except the first are ignored.
pub fn query_row<T>(&self, sql: &str, params: &[&ToSql], f: |SqliteRow| -> T) -> T {
let mut stmt = self.prepare(sql).unwrap();
let mut rows = stmt.query(params).unwrap();
f(rows.next().expect("Query did not return a row").unwrap())
}
/// Prepare a SQL statement for execution.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn insert_new_people(conn: &SqliteConnection) -> SqliteResult<()> {
/// let mut stmt = try!(conn.prepare("INSERT INTO People (name) VALUES (?)"));
/// try!(stmt.execute(&[&"Joe Smith"]));
/// try!(stmt.execute(&[&"Bob Jones"]));
/// Ok(())
/// }
/// ```
pub fn prepare<'a>(&'a self, sql: &str) -> SqliteResult<SqliteStatement<'a>> {
self.db.borrow_mut().prepare(self, sql)
}
/// Close the SQLite connection.
///
/// This is functionally equivalent to the `Drop` implementation for `SqliteConnection` except
/// that it returns any error encountered to the caller.
pub fn close(self) -> SqliteResult<()> {
self.db.borrow_mut().close()
}
@ -119,7 +294,10 @@ struct InnerSqliteConnection {
}
bitflags! {
#[repr(C)] flags SqliteOpenFlags: c_int {
#[doc = "Flags for opening SQLite database connections."]
#[doc = "See [sqlite3_open_v2](http://www.sqlite.org/c3ref/open.html) for details."]
#[repr(C)]
flags SqliteOpenFlags: c_int {
const SQLITE_OPEN_READ_ONLY = 0x00000001,
const SQLITE_OPEN_READ_WRITE = 0x00000002,
const SQLITE_OPEN_CREATE = 0x00000004,
@ -211,6 +389,7 @@ impl Drop for InnerSqliteConnection {
}
}
/// A prepared statement.
pub struct SqliteStatement<'conn> {
conn: &'conn SqliteConnection,
stmt: *mut ffi::sqlite3_stmt,
@ -222,6 +401,24 @@ impl<'conn> SqliteStatement<'conn> {
SqliteStatement{ conn: conn, stmt: stmt, needs_reset: false }
}
/// Execute the prepared statement.
///
/// On success, returns the number of rows that were changed or inserted or deleted (via
/// `sqlite3_changes`).
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn update_rows(conn: &SqliteConnection) -> SqliteResult<()> {
/// let mut stmt = try!(conn.prepare("UPDATE foo SET bar = 'baz' WHERE qux = ?"));
///
/// try!(stmt.execute(&[&1i32]));
/// try!(stmt.execute(&[&2i32]));
///
/// Ok(())
/// }
/// ```
pub fn execute(&mut self, params: &[&ToSql]) -> SqliteResult<uint> {
self.reset_if_needed();
@ -243,6 +440,25 @@ impl<'conn> SqliteStatement<'conn> {
}
}
/// Execute the prepared statement, returning an iterator over the resulting rows.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn get_names(conn: &SqliteConnection) -> SqliteResult<Vec<String>> {
/// let mut stmt = try!(conn.prepare("SELECT name FROM people"));
/// let mut rows = try!(stmt.query([]));
///
/// let mut names = Vec::new();
/// for result_row in rows {
/// let row = try!(result_row);
/// names.push(row.get(0));
/// }
///
/// Ok(names)
/// }
/// ```
pub fn query<'a>(&'a mut self, params: &[&ToSql]) -> SqliteResult<SqliteRows<'a>> {
self.reset_if_needed();
@ -258,6 +474,10 @@ impl<'conn> SqliteStatement<'conn> {
}
}
/// Consumes the statement.
///
/// Functionally equivalent to the `Drop` implementation, but allows callers to see any errors
/// that occur.
pub fn finalize(mut self) -> SqliteResult<()> {
self.finalize_()
}
@ -290,6 +510,7 @@ impl<'conn> Drop for SqliteStatement<'conn> {
}
}
/// An iterator over the resulting rows of a query.
pub struct SqliteRows<'stmt> {
stmt: &'stmt SqliteStatement<'stmt>,
current_row: Rc<Cell<c_int>>,
@ -326,6 +547,7 @@ impl<'stmt> Iterator<SqliteResult<SqliteRow<'stmt>>> for SqliteRows<'stmt> {
}
}
/// A single result row of a query.
pub struct SqliteRow<'stmt> {
stmt: &'stmt SqliteStatement<'stmt>,
current_row: Rc<Cell<c_int>>,
@ -333,10 +555,44 @@ pub struct SqliteRow<'stmt> {
}
impl<'stmt> SqliteRow<'stmt> {
/// Get the value of a particular column of the result row.
///
/// Note that `SqliteRow` falls into the "semi-safe" category of rusqlite. When you are
/// retrieving the rows of a query, a row becomes stale once you have requested the next row,
/// and the values can no longer be retrieved. In general (when using a loop over the rows, for
/// example) this isn't an issue, but it means you cannot do something like this:
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn bad_function_will_panic(conn: &SqliteConnection) -> SqliteResult<i64> {
/// let mut stmt = try!(conn.prepare("SELECT id FROM my_table"));
/// let mut rows = try!(stmt.query([]));
///
/// let row0 = try!(rows.next().unwrap());
/// // row 0 is value now...
///
/// let row1 = try!(rows.next().unwrap());
/// // row 0 is now STALE, and row 1 is valid
///
/// let my_id = row0.get(0); // WILL PANIC because row 0 is stale
/// Ok(my_id)
/// }
/// ```
///
/// ## Failure
///
/// Panics if `idx` is outside the range of columns in the returned query or if this row
/// is stale.
pub fn get<T: FromSql>(&self, idx: c_int) -> T {
self.get_opt(idx).unwrap()
}
/// Attempt to get the value of a particular column of the result row.
///
/// ## Failure
///
/// Returns a `SQLITE_MISUSE`-coded `SqliteError` if `idx` is outside the valid column range
/// for this row or if this row is stale.
pub fn get_opt<T: FromSql>(&self, idx: c_int) -> SqliteResult<T> {
if self.row_idx != self.current_row.get() {
return Err(SqliteError{ code: ffi::SQLITE_MISUSE,

62
src/transaction.rs
View File

@ -1,11 +1,35 @@
use {SqliteResult, SqliteConnection};
/// Options for transaction behavior. See [BEGIN
/// TRANSACTION](http://www.sqlite.org/lang_transaction.html) for details.
pub enum SqliteTransactionBehavior {
SqliteTransactionDeferred,
SqliteTransactionImmediate,
SqliteTransactionExclusive,
}
/// Represents a transaction on a database connection.
///
/// ## Note
///
/// Transactions will roll back by default. Use the `set_commit` or `commit` methods to commit the
/// transaction.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// # fn do_queries_part_1(conn: &SqliteConnection) -> SqliteResult<()> { Ok(()) }
/// # fn do_queries_part_2(conn: &SqliteConnection) -> SqliteResult<()> { Ok(()) }
/// fn perform_queries(conn: &SqliteConnection) -> SqliteResult<()> {
/// let tx = try!(conn.transaction());
///
/// try!(do_queries_part_1(conn)); // tx causes rollback if this fails
/// try!(do_queries_part_2(conn)); // tx causes rollback if this fails
///
/// tx.commit()
/// }
/// ```
pub struct SqliteTransaction<'conn> {
conn: &'conn SqliteConnection,
depth: u32,
@ -14,6 +38,7 @@ pub struct SqliteTransaction<'conn> {
}
impl<'conn> SqliteTransaction<'conn> {
/// Begin a new transaction. Cannot be nested; see `savepoint` for nested transactions.
pub fn new(conn: &SqliteConnection,
behavior: SqliteTransactionBehavior) -> SqliteResult<SqliteTransaction> {
let query = match behavior {
@ -26,6 +51,32 @@ impl<'conn> SqliteTransaction<'conn> {
})
}
/// Starts a new [savepoint](http://www.sqlite.org/lang_savepoint.html), allowing nested
/// transactions.
///
/// ## Note
///
/// Just like outer level transactions, savepoint transactions rollback by default.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// # fn perform_queries_part_1_succeeds(conn: &SqliteConnection) -> bool { true }
/// fn perform_queries(conn: &SqliteConnection) -> SqliteResult<()> {
/// let tx = try!(conn.transaction());
///
/// {
/// let sp = try!(tx.savepoint());
/// if perform_queries_part_1_succeeds(conn) {
/// try!(sp.commit());
/// }
/// // otherwise, sp will rollback
/// }
///
/// tx.commit()
/// }
/// ```
pub fn savepoint<'a>(&'a self) -> SqliteResult<SqliteTransaction<'a>> {
self.conn.execute_batch("SAVEPOINT sp").map(|_| {
SqliteTransaction{
@ -34,22 +85,27 @@ impl<'conn> SqliteTransaction<'conn> {
})
}
/// Returns whether or not the transaction is currently set to commit.
pub fn will_commit(&self) -> bool {
self.commit
}
/// Returns whether or not the transaction is currently set to rollback.
pub fn will_rollback(&self) -> bool {
!self.commit
}
/// Set the transaction to commit at its completion.
pub fn set_commit(&mut self) {
self.commit = true
}
/// Set the transaction to rollback at its completion.
pub fn set_rollback(&mut self) {
self.commit = false
}
/// A convenience method which consumes and commits a transaction.
pub fn commit(mut self) -> SqliteResult<()> {
self.commit_()
}
@ -59,6 +115,7 @@ impl<'conn> SqliteTransaction<'conn> {
self.conn.execute_batch(if self.depth == 0 { "COMMIT" } else { "RELEASE sp" })
}
/// A convenience method which consumes and rolls back a transaction.
pub fn rollback(mut self) -> SqliteResult<()> {
self.rollback_()
}
@ -68,6 +125,11 @@ impl<'conn> SqliteTransaction<'conn> {
self.conn.execute_batch(if self.depth == 0 { "ROLLBACK" } else { "ROLLBACK TO sp" })
}
/// Consumes the transaction, committing or rolling back according to the current setting
/// (see `will_commit`, `will_rollback`).
///
/// Functionally equivalent to the `Drop` implementation, but allows callers to see any
/// errors that occur.
pub fn finish(mut self) -> SqliteResult<()> {
self.finish_()
}

67
src/types.rs
View File

@ -1,3 +1,57 @@
//! Traits dealing with SQLite data types.
//!
//! SQLite uses a [dynamic type system](https://www.sqlite.org/datatype3.html). Implementations of
//! the `ToSql` and `FromSql` traits are provided for the basic types that SQLite provides methods
//! for:
//!
//! * C integers and doubles (`c_int` and `c_double`)
//! * Strings (`String` and `&str`)
//! * Blobs (`Vec<u8>` and `&[u8]`)
//!
//! Additionally, because it is such a common data type, implementations are provided for
//! `time::Timespec` that use a string for storage (using the same format string,
//! `"%Y-%m-%d %H:%M:%S"`, as SQLite's builtin
//! [datetime](https://www.sqlite.org/lang_datefunc.html) function. Note that this storage
//! truncates timespecs to the nearest second. If you want different storage for timespecs, you can
//! use a newtype. For example, to store timespecs as doubles:
//!
//! `ToSql` and `FromSql` are also implemented for `Option<T>` where `T` implements `ToSql` or
//! `FromSql` for the cases where you want to know if a value was NULL (which gets translated to
//! `None`). If you get a value that was NULL in SQLite but you store it into a non-`Option` value
//! in Rust, you will get a "sensible" zero value - 0 for numeric types (including timespecs), an
//! empty string, or an empty vector of bytes.
//!
//! ```rust,ignore
//! extern crate rusqlite;
//! extern crate libc;
//!
//! use rusqlite::types::{FromSql, ToSql};
//! use rusqlite::{ffi, SqliteResult};
//! use libc::c_int;
//! use time;
//!
//! pub struct TimespecSql(pub time::Timespec);
//!
//! impl FromSql for TimespecSql {
//! unsafe fn column_result(stmt: *mut ffi::sqlite3_stmt, col: c_int)
//! -> SqliteResult<TimespecSql> {
//! let as_f64_result = FromSql::column_result(stmt, col);
//! as_f64_result.map(|as_f64: f64| {
//! TimespecSql(time::Timespec{ sec: as_f64.trunc() as i64,
//! nsec: (as_f64.fract() * 1.0e9) as i32 })
//! })
//! }
//! }
//!
//! impl ToSql for TimespecSql {
//! unsafe fn bind_parameter(&self, stmt: *mut ffi::sqlite3_stmt, col: c_int) -> c_int {
//! let TimespecSql(ts) = *self;
//! let as_f64 = ts.sec as f64 + (ts.nsec as f64) / 1.0e9;
//! as_f64.bind_parameter(stmt, col)
//! }
//! }
//! ```
extern crate time;
use libc::{c_int, c_double};
@ -9,10 +63,12 @@ use super::{SqliteResult, SqliteError};
const SQLITE_DATETIME_FMT: &'static str = "%Y-%m-%d %H:%M:%S";
/// A trait for types that can be converted into SQLite values.
pub trait ToSql {
unsafe fn bind_parameter(&self, stmt: *mut ffi::sqlite3_stmt, col: c_int) -> c_int;
}
/// A trait for types that can be created from a SQLite value.
pub trait FromSql {
unsafe fn column_result(stmt: *mut ffi::sqlite3_stmt, col: c_int) -> SqliteResult<Self>;
}
@ -75,6 +131,17 @@ impl<T: ToSql> ToSql for Option<T> {
}
}
/// Empty struct that can be used to fill in a query parameter as `NULL`.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// # use rusqlite::types::{Null};
/// fn insert_null(conn: &SqliteConnection) -> SqliteResult<uint> {
/// conn.execute("INSERT INTO people (name) VALUES (?)", &[&Null])
/// }
/// ```
pub struct Null;
impl ToSql for Null {