PostgreSQL for Schemamama

A PostgreSQL adapter for the lightweight database migration system Schemamama. Depends on the postgres crate.

Installation

If you're using Cargo, just add Schemamama to your Cargo.toml:

toml [dependencies] schemamama = "0.0.11" schemamama_postgres = "0.0.8" postgres = "0.11"

Usage

First, define some migrations:

```rust

[macro_use]

extern crate schemamama; extern crate schemamama_postgres; extern crate postgres;

use schemamama::{Migration, Migrator}; use schemamama_postgres::{PostgresAdapter, PostgresMigration};

struct CreateUsers; // Instead of using sequential numbers (1, 2, 3...), you may choose to use a collaborative // versioning scheme, such as epoch timestamps. migration!(CreateUsers, 1, "create users table");

impl PostgresMigration for CreateUsers { fn up(&self, transaction: &postgres::Transaction) -> Result<(), PostgresError> { transaction.execute("CREATE TABLE users (id BIGINT PRIMARY KEY);", &[]) }

fn down(&self, transaction: &postgres::Transaction) -> Result<(), PostgresError> {
    transaction.execute("DROP TABLE users;", &[])
}

}

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); ```

Testing

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.

To-do