public override ICoreController Execute() {
// 1. Create our migration controller
this.MigrationController = new MigrationController() {
// 2. Tell the migration controller where it should send it's commands.
BubbleObjects = {
// Pipe all commands to this controller, which is in turn passed onto Program.cs
// and eventually to Potato Database controller.
this
},
// 3. Setup a stream for us to track changes on.
Settings = new MigrationSettings() {
Origin = MigrationOrigin.Plugin,
// This name should be unique to your plugin. You could even use your plugin GUID,
// but you might want to combine your guid with the connection guid, if you require
// migrations on a per-plugin, per-connection basis (a store for each connection)
Name = "Potato.Examples.Database"
},
// 4. Migrations are run in order in this list. You should append database changes onto
// this chain *whenever* you make changes.
// If you always ADD to this list then every release you have will automatically update
// the database schematic, if the database being used requires a schematic.
// A single migration is just executable code, so you can do any number of commands within
// this migration. You could even do file structure changes in here if you wanted.
Migrations = {
// Version 1.0.0.0
new Migration() {
// Up, moving upstream in changes.
Up = () => {
ICommandResult result = this.Bubble(
CommandBuilder.DatabaseQuery(
new Create()
// You should namespace/prefix your collections/tables to avoid clashes with other plugins
.Collection("Potato_Example_Database_Users")
.Modifier(new IfNotExists())
.Field("Name", 255)
.Field("Stamp", new DateTimeType())
)
);
return result.Now.Queries.First().DescendantsAndSelf<Error>().Any() == false;
},
// Down, moving downstream in changes (do the opposite of Up)
Down = () => {
// Including Down is not critical when moving upstream, but it's good
// practice to include Down. We may in the future include plugin uninstalling
// and down migrations would allow the database to be uninstalled.
ICommandResult result = this.Bubble(
CommandBuilder.DatabaseQuery(
new Drop()
.Collection("Potato_Example_Database_Users")
)
);
return result.Now.Queries.First().DescendantsAndSelf<Error>().Any() == false;
}
},
// Pretend you released 1.0.0.0, then released an update later
// Version 1.0.0.1
new Migration() {
Up = () => {
// Add another field to our example
ICommandResult result = this.Bubble(
CommandBuilder.DatabaseQuery(
new Alter()
.Collection("Potato_Example_Database_Users")
.Method(
new Create()
.Field("Age", new IntegerType())
)
)
);
return result.Now.Queries.First().DescendantsAndSelf<Error>().Any() == false;
},
Down = () => {
// Drop the field, so people can revert this migration or uninstall can go
// through the motions.
ICommandResult result = this.Bubble(
CommandBuilder.DatabaseQuery(
new Alter()
.Collection("Potato_Example_Database_Users")
.Method(
new Drop()
.Field("Age", new IntegerType())
)
)
);
return result.Now.Queries.First().DescendantsAndSelf<Error>().Any() == false;
}
}
}
};
// 5. This will setup the basic migration tables if they do not exists already (your plugin
// might be first to use migrations). You should always call Execute on a newly formed ExecutableBase anyway.
this.MigrationController.Execute();
// 6. Now run through the migrations until we are at the latest version.
this.MigrationController.Up();
return base.Execute();
}
public TestMigrationTrackerHelper() {
Migrations = new MigrationController() {
// Bubble all commands to the database controller
BubbleObjects = new List<ICoreController>() {
TestDatabaseController.OpenSqLiteDriver()
},
Migrations = new List<IMigration>() {
new Migration() {
Up = () => {
Tracker = 1;
Counter++;
return true;
},
Down = () => {
Tracker = 0;
Counter++;
return true;
}
},
new Migration() {
Up = () => {
Tracker = 2;
Counter++;
return true;
},
Down = () => {
Tracker = 1;
Counter++;
return true;
}
},
new Migration() {
Up = () => {
Tracker = 3;
Counter++;
return true;
},
Down = () => {
Tracker = 2;
Counter++;
return true;
}
},
new Migration() {
Up = () => {
Tracker = 4;
Counter++;
return true;
},
Down = () => {
Tracker = 3;
Counter++;
return true;
}
}
},
Settings = new MigrationSettings() {
// Create a random stream name
Name = StringExtensions.RandomString(10),
// Just use Core as the origin for testing
Origin = MigrationOrigin.Core
}
}.Execute() as MigrationController;
}
public void TestMigrationUpFromNothingButCanceled() {
int counter = 0;
var migrations = new MigrationController() {
// Bubble all commands to the database controller
BubbleObjects = new List<ICoreController>() {
TestDatabaseController.OpenSqLiteDriver()
},
Migrations = new List<IMigration>() {
new Migration() {
Up = () => {
counter++;
return false;
},
Down = () => {
counter++;
return false;
}
}
},
Settings = new MigrationSettings() {
// Create a random stream name
Name = StringExtensions.RandomString(10),
// Just use Core as the origin for testing
Origin = MigrationOrigin.Core
}
};
migrations.Execute();
migrations.Up();
Assert.AreEqual(1, counter);
Assert.AreEqual(0, migrations.FindCurrentVersion());
}
