DatabaseMigrator

public struct DatabaseMigrator

A DatabaseMigrator registers and applies database migrations.

Migrations are named blocks of SQL statements that are guaranteed to be applied in order, once and only once.

When a user upgrades your application, only non-applied migration are run.

Usage:

var migrator = DatabaseMigrator()

// v1.0 database
migrator.registerMigration("createAuthors") { db in
    try db.execute("""
        CREATE TABLE authors (
            id INTEGER PRIMARY KEY,
            creationDate TEXT,
            name TEXT NOT NULL
        )
        """)
}

migrator.registerMigration("createBooks") { db in
    try db.execute("""
        CREATE TABLE books (
            uuid TEXT PRIMARY KEY,
            authorID INTEGER NOT NULL
                     REFERENCES authors(id)
                     ON DELETE CASCADE ON UPDATE CASCADE,
            title TEXT NOT NULL
        )
        """)
}

// v2.0 database
migrator.registerMigration("AddBirthYearToAuthors") { db in
    try db.execute("ALTER TABLE authors ADD COLUMN birthYear INT")
}

try migrator.migrate(dbQueue)