Android - DBflow migration script

Question

I am trying to learn about DBFlow, because in the project that I am working right now, the previous guy decided to use it. So in the database class I have this:

@Database(name = ConstructDB.NAME, version = ConstructDB.VERSION)
public class ConstructDB {
  public static final String NAME = "construct_v3";
  public static final int VERSION = 18;

  @Migration(version = 17, database = ConstructDB.class)
  public static class Migration17 extends AlterTableMigration<Task> {
    public Migration17(Class<Task> table) {
      super(table);
    }

    @Override
    public void onPreMigrate() {
      super.onPreMigrate();
      addColumn(SQLiteType.INTEGER, NAMES.DB.READ_COUNT);
    }
  }
}

This is the previous migration script. So right now I want to add a new column to this same table. I did the required changes in the table class (like adding the column, the set and get method, etc). And I want to write a new script to accept my changes. So I did this:

@Database(name = ConstructDB.NAME, version = ConstructDB.VERSION)
public class ConstructDB {
  public static final String NAME = "construct_v3";
  public static final int VERSION = 19;

  @Migration(version = 18, database = ConstructDB.class)
  public static class Migration18 extends AlterTableMigration<Task> {
    public Migration18(Class<Task> table) {
      super(table);
    }

    @Override
    public void onPreMigrate() {
      super.onPreMigrate();
      addColumn(SQLiteType.TEXT, NAMES.DB.CATEGORY_ID);
    }
  }
}

But when I run the project I get lots of errors like:

error: cannot find symbol
import com.construct.v2.dagger.DaggerConstructComponent;

And mostly errors like this (something_table, which are all the tables in my database. This _table files are under the build folder and they are not to be edited):

error: cannot find symbol
import com.construct.v2.models.Attachment_Table;

If I return to the state I had before my changes (in the Task model and the migration script) the code runs just fine. So I think I am doing something wrong or skipping some step. How do I run the migration script? What other changes do I need to make?

Answer 1

You need to add new migration class for your changes. Migration version should be same as DB version. Also check if you are using right data types (is your ID String?).

See this guide for migrations: https://agrosner.gitbooks.io/dbflow/content/Migrations.html