# Rust-Postgres
A native PostgreSQL driver for Rust.
Documentation is available at https://sfackler.github.io/rust-postgres/doc/postgres
[](https://travis-ci.org/sfackler/rust-postgres)
You can integrate Rust-Postgres into your project through the [releases on crates.io](https://crates.io/crates/postgres):
```toml
# Cargo.toml
[dependencies]
postgres = "0.6"
```
## Overview
Rust-Postgres is a pure-Rust frontend for the popular PostgreSQL database. It
exposes a high level interface in the vein of JDBC or Go's `database/sql`
package.
```rust
extern crate postgres;
extern crate time;
use time::Timespec;
use postgres::{Connection, SslMode};
struct Person {
id: i32,
name: String,
time_created: Timespec,
data: Option<Vec<u8>>
}
fn main() {
let conn = Connection::connect("postgres://postgres@localhost", &SslMode::None)
.unwrap();
conn.execute("CREATE TABLE person (
id SERIAL PRIMARY KEY,
name VARCHAR NOT NULL,
time_created TIMESTAMP NOT NULL,
data BYTEA
)", &[]).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, $3)",
&[&me.name, &me.time_created, &me.data]).unwrap();
let stmt = conn.prepare("SELECT id, name, time_created, data FROM person")
.unwrap();
for row in stmt.query(&[]).unwrap() {
let person = Person {
id: row.get(0),
name: row.get(1),
time_created: row.get(2),
data: row.get(3)
};
println!("Found person {}", person.name);
}
}
```
## Requirements
* **Rust** - Rust-Postgres is developed against the nightly releases on
http://www.rust-lang.org.
* **PostgreSQL 7.4 or later** - Rust-Postgres speaks version 3 of the
PostgreSQL protocol, which corresponds to versions 7.4 and later. If your
version of Postgres was compiled in the last decade, you should be okay.
## Usage
### Connecting
Connect to a Postgres server using the standard URI format:
```rust
let conn = try!(Connection::connect("postgres://user:pass@host:port/database?arg1=val1&arg2=val2",
&SslMode::None));
```
`pass` may be omitted if not needed. `port` defaults to `5432` and `database`
defaults to the value of `user` if not specified. The driver supports `trust`,
`password`, and `md5` authentication.
Unix domain sockets can be used as well. The `host` portion of the URI should be
set to the absolute path to the directory containing the socket file. Since `/`
is a reserved character in URLs, the path should be URL encoded.
```rust
let conn = try!(Connection::connect("postgres://postgres@%2Frun%2Fpostgres", &SslMode::None));
```
Paths which contain non-UTF8 characters can be handled in a different manner;
see the documentation for details.
### Statement Preparation
Prepared statements can have parameters, represented as `$n` where `n` is an
index into the parameter array starting from 1:
```rust
let stmt = try!(conn.prepare("SELECT * FROM foo WHERE bar = $1 AND baz = $2"));
```
### Querying
A prepared statement can be executed with the `query` and `execute` methods.
Both methods take an array of parameters to bind to the query represented as
`&ToSql` trait objects. `execute` returns the number of rows affected by the
query (or 0 if not applicable):
```rust
let stmt = try!(conn.prepare("UPDATE foo SET bar = $1 WHERE baz = $2"));
let updates = try!(stmt.execute(&[&1i32, &"biz"]));
println!("{} rows were updated", updates);
```
`query` returns an iterator over the rows returned from the database. The
fields in a row can be accessed either by their indices or their column names,
though access by index is more efficient. Unlike statement parameters, result
columns are zero-indexed.
```rust
let stmt = try!(conn.prepare("SELECT bar, baz FROM foo"));
for row in try!(stmt.query(&[])) {
let bar: i32 = row.get(0);
let baz: String = row.get("baz");
println!("bar: {}, baz: {}", bar, baz);
}
```
In addition, `Connection` has a utility `execute` method which is useful if a
statement is only going to be executed once:
```rust
let updates = try!(conn.execute("UPDATE foo SET bar = $1 WHERE baz = $2",
&[&1i32, &"biz"]));
println!("{} rows were updated", updates);
```
### Transactions
The `transaction` method will start a new transaction. It returns a
`Transaction` object which has the functionality of a
`Connection` as well as methods to control the result of the
transaction:
```rust
let trans = try!(conn.transaction());
try!(trans.execute(...));
let stmt = try!(trans.prepare(...));
if the_coast_is_clear {
trans.set_commit();
}
try!(trans.finish());
```
The transaction will be active until the `Transaction` object falls out of
scope. A transaction will roll back by default. Nested transactions are
supported via savepoints.
### Type Correspondence
Rust-Postgres enforces a strict correspondence between Rust types and Postgres
types. The driver currently supports the following conversions:
<table>
<thead>
<tr>
<th>Rust Type</th>
<th>Postgres Type</th>
</tr>
</thead>
<tbody>
<tr>
<td>bool</td>
<td>BOOL</td>
</tr>
<tr>
<td>i8</td>
<td>"char"</td>
</tr>
<tr>
<td>i16</td>
<td>SMALLINT, SMALLSERIAL</td>
</tr>
<tr>
<td>i32</td>
<td>INT, SERIAL</td>
</tr>
<tr>
<td>u32</td>
<td>OID</td>
</tr>
<tr>
<td>i64</td>
<td>BIGINT, BIGSERIAL</td>
</tr>
<tr>
<td>f32</td>
<td>REAL</td>
</tr>
<tr>
<td>f64</td>
<td>DOUBLE PRECISION</td>
</tr>
<tr>
<td>str/String</td>
<td>VARCHAR, CHAR(n), TEXT, CITEXT</td>
</tr>
<tr>
<td>[u8]/Vec<u8></td>
<td>BYTEA</td>
</tr>
<tr>
<td>serialize::json::Json</td>
<td>JSON/JSONB</td>
</tr>
<tr>
<td>IpAddr</td>
<td>INET/CIDR</td>
</tr>
<tr>
<td>time::Timespec</td>
<td>TIMESTAMP, TIMESTAMP WITH TIME ZONE</td>
</tr>
<tr>
<td>
<a href="https://github.com/rust-lang/uuid">uuid::Uuid</a>
(<a href="#optional-features">optional</a>)
</td>
<td>UUID</td>
</tr>
<tr>
<td>std::collections::HashMap<String, Option<String>></td>
<td>HSTORE</td>
</tr>
</tbody>
</table>
More conversions can be defined by implementing the `ToSql` and `FromSql`
traits.
Support for Postgres arrays is located in the
[postgres-array](https://github.com/sfackler/rust-postgres-array) crate.
Support for Postgres ranges is located in the
[postgres-range](https://github.com/sfackler/rust-postgres-range) crate.
## Optional features
### UUID type
[UUID](http://www.postgresql.org/docs/9.4/static/datatype-uuid.html) support is
provided optionally by the `uuid` feature.
## Development
Like Rust itself, Rust-Postgres is still in the early stages of development, so
don't be surprised if APIs change and things break. If something's not working
properly, file an issue or submit a pull request!