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("createPersons") { db in
    try db.execute(
        "CREATE TABLE persons (" +
            "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, " +
            "ownerID INTEGER NOT NULL " +
            "        REFERENCES persons(id) " +
            "        ON DELETE CASCADE ON UPDATE CASCADE, " +
            "title TEXT NOT NULL" +
        ")")
}

// v2.0 database
migrator.registerMigration("AddAgeToPersons") { db in
    try db.execute("ALTER TABLE persons ADD COLUMN age INT")
}

try migrator.migrate(dbQueue)