I started up on android again and started using the SQLite database for the first time. Coming from rails I really wanted to have some kind of migrations for the database. I googled around and didn’t really see anything available so I made up a simple class that solves my problem.
Note that this hasn’t been used outside of my test app. I also have only created one migration with it so far, but I like how it went. An abstract class might also not be the best way to go, but I haven’t used it since college and wanted to try it out again.
src/org/oestrich/myapp/migrations/Migration.java
package org.oestrich.myapp.migrations;
import android.database.sqlite.SQLiteDatabase;
public abstract class Migration {
private SQLiteDatabase mDatabase;
public Migration(SQLiteDatabase database) {
mDatabase = database;
}
public abstract void up();
public abstract void down();
public SQLiteDatabase getDatabase() {
return mDatabase;
}
}
src/org/oestrich/myapp/migrations/InitialDatabase.java
package org.oestrich.myapp.migrations;
import android.database.sqlite.SQLiteDatabase;
public class InitialDatabase extends Migration {
public InitialDatabase(SQLiteDatabase database) {
super(database);
}
@Override
public void up() {
getDatabase().execSQL(
"CREATE TABLE my_model (_id INTEGER PRIMARY KEY AUTOINCREMENT);");
}
@Override
public void down() {
getDatabase().execSQL("DROP TABLE my_model;");
}
}
src/org/oestrich/myapp/database_helper.rb
package org.oestrich.myapp;
public class DatabaseHelper extends SQLiteOpenHelper {
// ...
@Override
public void onCreate(SQLiteDatabase db) {
try {
db.beginTransaction();
new InitialDatabase(db).up();
// Add more migrations here
db.setTransactionSuccessful();
} finally {
db.endTransaction();
}
}
// ...
}
