# Rust-Postgres A native PostgreSQL driver for Rust. Documentation is available at https://sfackler.github.io/doc/postgres [](https://travis-ci.org/sfackler/rust-postgres) ```toml # Cargo.toml [dependencies.postgres] git = "https://github.com/sfackler/rust-postgres.git" ``` ## 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> } 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".into_string(), time_created: time::get_time(), data: None }; conn.execute("INSERT INTO person (name, time_created, data) VALUES ($1, $2, $3)", &[&me.name, &me.time_created, &me.data]).unwrap(); let stmt = conn.prepare("SELECT id, name, time_created, data FROM person") .unwrap(); for row in stmt.query(&[]).unwrap() { let person = Person { id: row.get(0), name: row.get(1), time_created: row.get(2), data: row.get(3) }; println!("Found person {}", person.name); } } ``` ## Requirements * **Rust** - Rust-Postgres is developed against the *master* branch of the Rust repository. It will most likely not build against the versioned releases on http://www.rust-lang.org. * **PostgreSQL 7.4 or later** - Rust-Postgres speaks version 3 of the PostgreSQL protocol, which corresponds to versions 7.4 and later. If your version of Postgres was compiled in the last decade, you should be okay. ## Usage ### Connecting Connect to a Postgres server using the standard URI format: ```rust let conn = try!(Connection::connect("postgres://user:pass@host:port/database?arg1=val1&arg2=val2", &SslMode::None)); ``` `pass` may be omitted if not needed. `port` defaults to `5432` and `database` defaults to the value of `user` if not specified. The driver supports `trust`, `password`, and `md5` authentication. Unix domain sockets can be used as well. The `host` portion of the URI should be set to the absolute path to the directory containing the socket file. Since `/` is a reserved character in URLs, the path should be URL encoded. ```rust let conn = try!(Connection::connect("postgres://postgres@%2Frun%2Fpostgres", &SslMode::None)); ``` Paths which contain non-UTF8 characters can be handled in a different manner; see the documentation for details. ### Statement Preparation Prepared statements can have parameters, represented as `$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:

Rust Type	Postgres Type
bool	BOOL
i8	"char"
i16	SMALLINT, SMALLSERIAL
i32	INT, SERIAL
i64	BIGINT, BIGSERIAL
f32	REAL
f64	DOUBLE PRECISION
str/String	VARCHAR, CHAR(n), TEXT
[u8]/Vec<u8>	BYTEA
serialize::json::Json	JSON
time::Timespec	TIMESTAMP, TIMESTAMP WITH TIME ZONE
uuid::Uuid (optional)	UUID
types::range::Range<i32>	INT4RANGE
types::range::Range<i64>	INT8RANGE
types::range::Range<Timespec>	TSRANGE, TSTZRANGE
types::array::ArrayBase<Option<bool>>	BOOL[], BOOL[][], ...
types::array::ArrayBase<Option<Vec<u8>>>	BYTEA[], BYTEA[][], ...
types::array::ArrayBase<Option<i8>>	"char"[], "char"[][], ...
types::array::ArrayBase<Option<i16>>	INT2[], INT2[][], ...
types::array::ArrayBase<Option<i32>>	INT4[], INT4[][], ...
types::array::ArrayBase<Option<String>>	TEXT[], CHAR(n)[], VARCHAR[], TEXT[][], ...
types::array::ArrayBase<Option<Json>>	JSON[], JSON[][], ...
types::array::ArrayBase<Option<i64>>	INT8[], INT8[][], ...
types::array::ArrayBase<Option<Timespec>>	TIMESTAMP[], TIMESTAMPTZ[], TIMESTAMP[][], ...
types::array::ArrayBase<Option<f32>>	FLOAT4[], FLOAT4[][], ...
types::array::ArrayBase<Option<f64>>	FLOAT8[], FLOAT8[][], ...
types::array::ArrayBase<Option<Range<i32>>>	INT4RANGE[], INT4RANGE[][], ...
types::array::ArrayBase<Option<Range<Timespec>>>	TSRANGE[], TSTZRANGE[], TSRANGE[][], ...
types::array::ArrayBase<Option<Range<i64>>>	INT8RANGE[], INT8RANGE[][], ...
std::collections::HashMap<String, Option<String>>	HSTORE

More conversions can be defined by implementing the `ToSql` and `FromSql` traits. ## Optional features ### UUID type [UUID](http://www.postgresql.org/docs/9.4/static/datatype-uuid.html) support is provided optionally by the `uuid` feature. It is enabled by default. To disable support for optional features, add `default-features = false` to your Cargo manifest: ```toml [dependencies.postgres] git = ... default-features = false features = [...] ``` ## 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!