297 lines
9.9 KiB
Markdown
297 lines
9.9 KiB
Markdown
# Rust-Postgres
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A native PostgreSQL driver for Rust.
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[Documentation](https://sfackler.github.io/rust-postgres/doc/v0.9.6/postgres)
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[](https://travis-ci.org/sfackler/rust-postgres) [](https://crates.io/crates/postgres)
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You can integrate Rust-Postgres into your project through the [releases on crates.io](https://crates.io/crates/postgres):
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```toml
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# Cargo.toml
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[dependencies]
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postgres = "0.9"
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```
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## Overview
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Rust-Postgres is a pure-Rust frontend for the popular PostgreSQL database. It
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exposes a high level interface in the vein of JDBC or Go's `database/sql`
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package.
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```rust
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extern crate postgres;
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use postgres::{Connection, SslMode};
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struct Person {
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id: i32,
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name: String,
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data: Option<Vec<u8>>
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}
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fn main() {
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let conn = Connection::connect("postgres://postgres@localhost", &SslMode::None)
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.unwrap();
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conn.execute("CREATE TABLE person (
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id SERIAL PRIMARY KEY,
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name VARCHAR NOT NULL,
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data BYTEA
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)", &[]).unwrap();
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let me = Person {
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id: 0,
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name: "Steven".to_string(),
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data: None
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};
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conn.execute("INSERT INTO person (name, data) VALUES ($1, $2)",
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&[&me.name, &me.data]).unwrap();
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let stmt = conn.prepare("SELECT id, name, data FROM person").unwrap();
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for row in stmt.query(&[]).unwrap() {
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let person = Person {
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id: row.get(0),
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name: row.get(1),
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data: row.get(2)
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};
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println!("Found person {}", person.name);
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}
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}
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```
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## Requirements
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* **Rust** - Rust-Postgres is developed against the 1.2 release of Rust
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available on http://www.rust-lang.org. It should also compile against more
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recent releases.
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* **PostgreSQL 7.4 or later** - Rust-Postgres speaks version 3 of the
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PostgreSQL protocol, which corresponds to versions 7.4 and later. If your
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version of Postgres was compiled in the last decade, you should be okay.
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## Usage
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### Connecting
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Connect to a Postgres server using the standard URI format:
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```rust
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let conn = try!(Connection::connect("postgres://user:pass@host:port/database?arg1=val1&arg2=val2",
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&SslMode::None));
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```
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`pass` may be omitted if not needed. `port` defaults to `5432` and `database`
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defaults to the value of `user` if not specified. The driver supports `trust`,
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`password`, and `md5` authentication.
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Unix domain sockets can be used as well by activating the `unix_socket` feature.
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The `host` portion of the URI should be set to the absolute path to the
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directory containing the socket file. Since `/` is a reserved character in
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URLs, the path should be URL encoded.
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```rust
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let conn = try!(Connection::connect("postgres://postgres@%2Frun%2Fpostgres", &SslMode::None));
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```
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Paths which contain non-UTF8 characters can be handled in a different manner;
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see the documentation for details.
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### Statement Preparation
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Prepared statements can have parameters, represented as `$n` where `n` is an
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index into the parameter array starting from 1:
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```rust
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let stmt = try!(conn.prepare("SELECT * FROM foo WHERE bar = $1 AND baz = $2"));
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```
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### Querying
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A prepared statement can be executed with the `query` and `execute` methods.
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Both methods take an array of parameters to bind to the query represented as
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`&ToSql` trait objects. `execute` returns the number of rows affected by the
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query (or 0 if not applicable):
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```rust
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let stmt = try!(conn.prepare("UPDATE foo SET bar = $1 WHERE baz = $2"));
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let updates = try!(stmt.execute(&[&1i32, &"biz"]));
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println!("{} rows were updated", updates);
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```
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`query` returns an iterator over the rows returned from the database. The
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fields in a row can be accessed either by their indices or their column names,
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though access by index is more efficient. Unlike statement parameters, result
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columns are zero-indexed.
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```rust
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let stmt = try!(conn.prepare("SELECT bar, baz FROM foo"));
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for row in try!(stmt.query(&[])) {
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let bar: i32 = row.get(0);
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let baz: String = row.get("baz");
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println!("bar: {}, baz: {}", bar, baz);
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}
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```
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In addition, `Connection` has a utility `execute` method which is useful if a
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statement is only going to be executed once:
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```rust
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let updates = try!(conn.execute("UPDATE foo SET bar = $1 WHERE baz = $2",
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&[&1i32, &"biz"]));
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println!("{} rows were updated", updates);
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```
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### Transactions
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The `transaction` method will start a new transaction. It returns a
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`Transaction` object which has the functionality of a
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`Connection` as well as methods to control the result of the
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transaction:
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```rust
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let trans = try!(conn.transaction());
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try!(trans.execute(...));
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let stmt = try!(trans.prepare(...));
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if the_coast_is_clear {
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trans.set_commit();
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}
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try!(trans.finish());
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```
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The transaction will be active until the `Transaction` object falls out of
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scope. A transaction will roll back by default. Nested transactions are
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supported via savepoints.
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### Type Correspondence
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Rust-Postgres enforces a strict correspondence between Rust types and Postgres
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types. The driver currently supports the following conversions:
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<table>
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<thead>
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<tr>
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<th>Rust Type</th>
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<th>Postgres Type</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>bool</td>
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<td>BOOL</td>
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</tr>
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<tr>
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<td>i8</td>
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<td>"char"</td>
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</tr>
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<tr>
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<td>i16</td>
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<td>SMALLINT, SMALLSERIAL</td>
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</tr>
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<tr>
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<td>i32</td>
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<td>INT, SERIAL</td>
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</tr>
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<tr>
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<td>u32</td>
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<td>OID</td>
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</tr>
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<tr>
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<td>i64</td>
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<td>BIGINT, BIGSERIAL</td>
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</tr>
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<tr>
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<td>f32</td>
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<td>REAL</td>
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</tr>
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<tr>
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<td>f64</td>
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<td>DOUBLE PRECISION</td>
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</tr>
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<tr>
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<td>str/String</td>
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<td>VARCHAR, CHAR(n), TEXT, CITEXT</td>
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</tr>
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<tr>
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<td>[u8]/Vec<u8></td>
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<td>BYTEA</td>
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</tr>
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<tr>
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<td>
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<a href="https://github.com/rust-lang/rustc-serialize">serialize::json::Json</a>
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and
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<a href="https://github.com/erickt/serde">serde::json::Value</a>
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(<a href="#optional-features">optional</a>)
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</td>
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<td>JSON, JSONB</td>
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</tr>
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<tr>
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<td>
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<a href="https://github.com/rust-lang/time">time::Timespec</a>
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and
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<a href="https://github.com/lifthrasiir/rust-chrono">chrono::NaiveDateTime</a>
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(<a href="#optional-features">optional</a>)
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</td>
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<td>TIMESTAMP</td>
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</tr>
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<tr>
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<td>
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<a href="https://github.com/rust-lang/time">time::Timespec</a>,
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<a href="https://github.com/lifthrasiir/rust-chrono">chrono::DateTime<UTC></a>,
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<a href="https://github.com/lifthrasiir/rust-chrono">chrono::DateTime<Local></a>,
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and
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<a href="https://github.com/lifthrasiir/rust-chrono">chrono::DateTime<FixedOffset></a>
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(<a href="#optional-features">optional</a>)
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</td>
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<td>TIMESTAMP WITH TIME ZONE</td>
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</tr>
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<tr>
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<td>
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<a href="https://github.com/lifthrasiir/rust-chrono">chrono::NaiveDate</a>
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(<a href="#optional-features">optional</a>)
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</td>
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<td>DATE</td>
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</tr>
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<tr>
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<td>
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<a href="https://github.com/lifthrasiir/rust-chrono">chrono::NaiveTime</a>
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(<a href="#optional-features">optional</a>)
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</td>
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<td>TIME</td>
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</tr>
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<tr>
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<td>
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<a href="https://github.com/rust-lang/uuid">uuid::Uuid</a>
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(<a href="#optional-features">optional</a>)
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</td>
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<td>UUID</td>
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</tr>
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<tr>
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<td>HashMap<String, Option<String>></td>
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<td>HSTORE</td>
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</tr>
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</tbody>
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</table>
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More conversions can be defined by implementing the `ToSql` and `FromSql`
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traits.
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Support for array types is located in the
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[postgres-array](https://github.com/sfackler/rust-postgres-array) crate.
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Support for range types is located in the
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[postgres-range](https://github.com/sfackler/rust-postgres-range) crate.
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Support for the large object API is located in the
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[postgres-large-object](https://github.com/sfackler/rust-postgres-large-object) crate.
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## Optional features
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### Unix socket connections
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Support for connections through Unix domain sockets is provided optionally by
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the `unix_socket` feature. It is only available on "unixy" platforms such as
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OSX, BSD and Linux.
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### UUID type
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[UUID](http://www.postgresql.org/docs/9.4/static/datatype-uuid.html) support is
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provided optionally by the `uuid` feature, which adds `ToSql` and `FromSql`
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implementations for `uuid`'s `Uuid` type.
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### JSON/JSONB types
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[JSON and JSONB](http://www.postgresql.org/docs/9.4/static/datatype-json.html)
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support is provided optionally by the `rustc-serialize` feature, which adds
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`ToSql` and `FromSql` implementations for `rustc-serialize`'s `Json` type, and
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the `serde` feature, which adds implementations for `serde`'s `json::Value`
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type.
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### TIMESTAMP/TIMESTAMPTZ/DATE/TIME types
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[Date and Time](http://www.postgresql.org/docs/9.1/static/datatype-datetime.html)
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support is provided optionally by the `time` feature, which adds `ToSql` and
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`FromSql` implementations for `time`'s `Timespec` type, or the `chrono`
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feature, which adds `ToSql` and `FromSql` implementations for `chrono`'s
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`DateTime`, `NaiveDateTime`, `NaiveDate` and `NaiveTime` types.
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