rust-postgres/README.md

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# Rust-Postgres
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A native PostgreSQL driver for Rust.
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Documentation is available at https://sfackler.github.io/rust-postgres/doc/postgres
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[![Build Status](https://travis-ci.org/sfackler/rust-postgres.png?branch=master)](https://travis-ci.org/sfackler/rust-postgres)
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You can integrate Rust-Postgres into your project through the [releases on crates.io](https://crates.io/crates/postgres):
```toml
# Cargo.toml
[dependencies]
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postgres = "0.6"
```
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## Overview
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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;
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extern crate time;
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use time::Timespec;
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use postgres::{Connection, SslMode};
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struct Person {
id: i32,
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name: String,
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time_created: Timespec,
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data: Option<Vec<u8>>
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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,
name VARCHAR NOT NULL,
time_created TIMESTAMP NOT NULL,
data BYTEA
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)", &[]).unwrap();
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let me = Person {
id: 0,
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name: "Steven".to_string(),
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time_created: time::get_time(),
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data: None
};
conn.execute("INSERT INTO person (name, time_created, data)
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VALUES ($1, $2, $3)",
&[&me.name, &me.time_created, &me.data]).unwrap();
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let stmt = conn.prepare("SELECT id, name, time_created, data FROM person")
.unwrap();
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for row in stmt.query(&[]).unwrap() {
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let person = Person {
id: row.get(0),
name: row.get(1),
time_created: row.get(2),
data: row.get(3)
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};
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println!("Found person {}", person.name);
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}
}
```
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## Requirements
* **Rust** - Rust-Postgres is developed against the nightly releases on
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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.
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## Usage
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### Connecting
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Connect to a Postgres server using the standard URI format:
```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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```
`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.
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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
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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.
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### Statement Preparation
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Prepared statements can have parameters, represented as `$n` where `n` is an
index into the parameter array starting from 1:
```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
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
`&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"));
let updates = try!(stmt.execute(&[&1i32, &"biz"]));
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println!("{} rows were updated", updates);
```
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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,
though access by index is more efficient. Unlike statement parameters, result
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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In addition, `Connection` has a utility `execute` method which is useful if a
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",
&[&1i32, &"biz"]));
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println!("{} rows were updated", updates);
```
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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
`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());
try!(trans.execute(...));
let stmt = try!(trans.prepare(...));
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if the_coast_is_clear {
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
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>
<thead>
<tr>
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<th>Rust Type</th>
<th>Postgres Type</th>
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</tr>
</thead>
<tbody>
<tr>
<td>bool</td>
<td>BOOL</td>
</tr>
<tr>
<td>i8</td>
<td>"char"</td>
</tr>
<tr>
<td>i16</td>
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<td>SMALLINT, SMALLSERIAL</td>
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</tr>
<tr>
<td>i32</td>
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<td>INT, SERIAL</td>
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</tr>
<tr>
<td>u32</td>
<td>OID</td>
</tr>
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<tr>
<td>i64</td>
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<td>BIGINT, BIGSERIAL</td>
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</tr>
<tr>
<td>f32</td>
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<td>REAL</td>
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</tr>
<tr>
<td>f64</td>
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<td>DOUBLE PRECISION</td>
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</tr>
<tr>
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<td>str/String</td>
<td>VARCHAR, CHAR(n), TEXT, CITEXT</td>
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</tr>
<tr>
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<td>[u8]/Vec&lt;u8&gt;</td>
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<td>BYTEA</td>
</tr>
<tr>
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<td>serialize::json::Json</td>
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<td>JSON/JSONB</td>
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</tr>
<tr>
<td>IpAddr</td>
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<td>INET/CIDR</td>
</tr>
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<tr>
<td>time::Timespec</td>
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<td>TIMESTAMP, TIMESTAMP WITH TIME ZONE</td>
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</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>
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<tr>
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<td>std::collections::HashMap&lt;String, Option&lt;String&gt;&gt;</td>
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<td>HSTORE</td>
</tr>
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</tbody>
</table>
More conversions can be defined by implementing the `ToSql` and `FromSql`
traits.
Support for Postgres arrays is located in the
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[postgres-array](https://github.com/sfackler/rust-postgres-array) crate.
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Support for Postgres ranges is located in the
[postgres-range](https://github.com/sfackler/rust-postgres-range) crate.
## Optional features
### 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.
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## Development
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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!