SQLiteMigrations

This library is in development stage. It does not yet implement every planned feature. Right now it only implements key features I needed for a project.

SQLiteMigrations is a .NET Portable Class Library (PCL) to enable database schema management for SQLitePCL.raw built on top of SQLitePCL.pretty.

This project was inspired by SQLiteMigrationManager.swift (from which I borrowed the README structure) and goose.

Concept

SQLiteMigrations works by introducing a __migrations table into the database:

CREATE TABLE __migrations (
  id INT NOT NULL
);

Each row in __migrations corresponds to a single migration that has been applied and represents a unique version of the schema. This schema supports any versioning scheme that is based on integers, but it is recommended that you utilize an integer that encodes a timestamp.

Usage

Have a look at the tests.

Initializing the database

You would first have to implement the interface IMigrationsProvider in order to provide the migrations to the migrator. When you are done with that you can define your configuration instance.

var config = new Configuration
{
  DBPath = DBPath,
  MigrationsProvider = new MigrationsProviderImplementation()
};

You can also provide a IMigrationsLogger implementation for logging of profiling information on each executed statement.

From there the process is really simple.

var migrator = new SQLiteMigrator(config);
migrator.init();

The init method call will create the database at the specified path if it does not exist already. Then it will check for the __migrations table and create it if is missing. It will then check for the current database schema version (initially 0) and retrieve all the migrations with version code higher than the current database schema version and execute them in order.

Creating a migration

Create a migration file:

$ touch 201704011234_add_phone_field_to_user.sql

SQLiteMigrations will only recognize filenames of the form <version>_<name>.sql. The following filenames are valid:

• 1.sql
• 2_add_new_table.sql
• 3_add-new-table.sql
• 4_add new table.sql

The file must be structured as follows:

--- database id 201704011234

--- database up

-- Upgrade your database
ALTER TABLE users ADD COLUMN phone VARCHAR(25);

--- database down

-- Downgrade your database
CREATE TABLE users_backup(name VARCHAR(50));
INSERT INTO users_backup SELECT name FROM users;
DROP TABLE users;
ALTER TABLE users_backup RENAME TO users;

The migration is ran inside a transaction so it can be rolled back in case of failure. Be careful not to try to begin a transaction since this would cause an error.

Installation

NuGet

To install SQLiteMigrations, run the following command in the Package Manager Console

Install-Package MallaCreativa.SQLiteMigrations

Or just go to the NuGet package gallery and add it to your project.

TODO

• Implement schema upgrading
• Implement schema downgrading
• Flexibility on schema migration process
• Information of schema version (and if it has migrations table)

Helping hands are totally wellcome.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b feature/my-new-feature or git checkout -b hotfix/my-hotfix)
3. Commit your changes (git commit -am 'Add some feature' or git commit -am 'Fix some error')
4. Push to the branch (git push origin feature/my-new-feature or git push origin hotfix/my-hotfix)
5. Create a new Pull Request
6. You're awesome! 👍

You can create the Pull Request before having completed the changes (or even before starting) to request feedback or ask for help for where to begin, just remember to keep [WIP] to let everyone know it is a Work In Progress before the name until your work is done.

Author

Jonatan Cardona Casas, jace.casas@gmail.com

License

Migrations is available under the MIT license. See the LICENSE file for more info.