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Lidarr/Migrator.net/Migrator.Framework/Migration.cs

119 lines
4.1 KiB
C#

#region License
//The contents of this file are subject to the Mozilla Public License
//Version 1.1 (the "License"); you may not use this file except in
//compliance with the License. You may obtain a copy of the License at
//http://www.mozilla.org/MPL/
//Software distributed under the License is distributed on an "AS IS"
//basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
//License for the specific language governing rights and limitations
//under the License.
#endregion
namespace Migrator.Framework
{
/// <summary>
/// A migration is a group of transformation applied to the database schema
/// (or sometimes data) to port the database from one version to another.
/// The <c>Up()</c> method must apply the modifications (eg.: create a table)
/// and the <c>Down()</c> method must revert, or rollback the modifications
/// (eg.: delete a table).
/// <para>
/// Each migration must be decorated with the <c>[Migration(0)]</c> attribute.
/// Each migration number (0) must be unique, or else a
/// <c>DuplicatedVersionException</c> will be trown.
/// </para>
/// <para>
/// All migrations are executed inside a transaction. If an exception is
/// thrown, the transaction will be rolledback and transformations wont be
/// applied.
/// </para>
/// <para>
/// It is best to keep a limited number of transformation inside a migration
/// so you can easely move from one version of to another with fine grain
/// modifications.
/// You should give meaningful name to the migration class and prepend the
/// migration number to the filename so they keep ordered, eg.:
/// <c>002_CreateTableTest.cs</c>.
/// </para>
/// <para>
/// Use the <c>Database</c> property to apply transformation and the
/// <c>Logger</c> property to output informations in the console (or other).
/// For more details on transformations see
/// <see cref="ITransformationProvider">ITransformationProvider</see>.
/// </para>
/// </summary>
/// <example>
/// The following migration creates a new Customer table.
/// (File <c>003_AddCustomerTable.cs</c>)
/// <code>
/// [Migration(3)]
/// public class AddCustomerTable : Migration
/// {
/// public override void Up()
/// {
/// Database.AddTable("Customer",
/// new Column("Name", typeof(string), 50),
/// new Column("Address", typeof(string), 100)
/// );
/// }
/// public override void Down()
/// {
/// Database.RemoveTable("Customer");
/// }
/// }
/// </code>
/// </example>
public abstract class Migration : IMigration
{
private ITransformationProvider _transformationProvider;
public string Name
{
get { return StringUtils.ToHumanName(GetType().Name); }
}
/// <summary>
/// Defines tranformations to port the database to the current version.
/// </summary>
public abstract void Up();
/// <summary>
/// This is run after the Up transaction has been committed
/// </summary>
public virtual void AfterUp()
{
}
/// <summary>
/// Defines transformations to revert things done in <c>Up</c>.
/// </summary>
public abstract void Down();
/// <summary>
/// This is run after the Down transaction has been committed
/// </summary>
public virtual void AfterDown()
{
}
/// <summary>
/// Represents the database.
/// <see cref="ITransformationProvider"></see>.
/// </summary>
/// <seealso cref="ITransformationProvider">Migration.Framework.ITransformationProvider</seealso>
public ITransformationProvider Database
{
get { return _transformationProvider; }
set { _transformationProvider = value; }
}
/// <summary>
/// This gets called once on the first migration object.
/// </summary>
public virtual void InitializeOnce(string[] args)
{
}
}
}