A PostgreSQL adapter for the lightweight database migration system
Schemamama. Depends on the
postgres crate.
If you're using Cargo, just add Schemamama to your Cargo.toml:
toml
[dependencies]
schemamama = "*"
schemamama_postgres = "*"
postgres = "0.8"
First, define some migrations:
```rust
extern crate schemamama; extern crate schemamama_postgres; extern crate postgres;
// Needed to apply the migration! macro:
use schemamama::Migration;
struct CreateUsers; // Instead of using sequential numbers (1, 2, 3...), you may instead choose to use a global // versioning scheme, such as epoch timestamps. migration!(CreateUsers, 1, "create users table");
impl PostgresMigration for CreateUsers { fn up(&self, transaction: &postgres::Transaction) { transaction.execute("CREATE TABLE users (id BIGINT PRIMARY KEY);", &[]).unwrap(); }
fn down(&self, transaction: &postgres::Transaction) {
transaction.execute("DROP TABLE users;", &[]).unwrap();
}
}
struct CreateProducts; migration!(CreateProducts, 2, "create products table");
impl PostgresMigration for CreateProducts { // ... } ```
Then, run the migrations!
``rust
let url = "postgres://postgres@localhost";
let connection = postgres::Connection::connect(url, &SslMode::None).unwrap();
let adapter = PostgresAdapter::new(&connection);
// Create the metadata tables necessary for tracking migrations. This is safe to call more than
// once (CREATE TABLE IF NOT EXISTS schemamama` is used internally):
adapter.setup_schema();
let mut migrator = Migrator::new(adapter);
migrator.register(Box::new(CreateUsers)); migrator.register(Box::new(CreateProducts));
// Execute migrations up to and including version 2: migrator.up(2); asserteq!(migrator.currentversion(), Some(2));
// Reverse all migrations: migrator.down(None); asserteq!(migrator.currentversion(), None); ```
To run cargo test, you must have PostgreSQL running locally with a user role
named postgres with login access to a database named postgres. All tests
will work in the pg_temp schema, so the database will not be modified.
schemamama).