This page contains frequently asked question about developing with greenDAO. If your question does not directly relate to developing, check the general FAQ.
General
Which Android version does greenDAO require?
greenDAO runs on Android versions 1.6 and higher.
What’s a good place to store SQLiteDatabase/DaoMaster/DaoSession?
As a rule of thumb it’s a good idea to store database related objects in Application scope. This way use can use the database/DAO objects across Activities. Leaving the database open for the life time of the application’s process makes things simple and efficient.
Can I use existing entity classes? Can I skip entity generation?
Yes. In your generator project, call setSkipGeneration(true) on entities you do not want to generate. Like this, you have the most possible control over your entities at the cost of manual maintenance. However, this is considered advanced usage and should be reserved for special cases only: the recommended way is to generate entities and use “keep sections” to inject custom code into them. If you choose to skip entity generation, you must either provide a constructor with all property fields in the order they were added in the generator project. Or alternatively, call setConstructors(false) on entities to make greenDAO use setters instead of the constructor to create entities.
What are primary key restrictions? (key types, composite keys, etc.)
To quote the modelling documentations: Currently, entities must have a long or Long property as their primary key. This is recommended practice for Android and SQLite. greenDAO is prepared to handle any primary key scenario in the future, but not everything is implemented completely yet. To work around this issue, you can use a long primary key and use an unique index for the intended “key” properties. Starting from greenDAO there’s limited support for String primary keys.
What are the rules for ProGuard?
public static java.lang.String TABLENAME;
}
-keep class **$Properties
Relations
After I insert/delete entries to/from a to-many relation, there are some issues.
Keep in mind, that relations entries are cached in the entity. Depending on your issue, you may have to make manually updates or reset your to-many relation. Please read the documentation on relations closely for details. Especially the section “Modelling To-One Relations” should be relevant to you.
Performance
Inserting/updating/deleting entities runs very slow. What’s wrong?
Probably, you are inserting/updating/deleting entities without using a transaction. Thus each operation is considered a transaction and SQLite needs to write to disk and do a file sync for each operation. Running all operations in a single transaction is essential for performance (and usually makes sense in terms of consistency). It will run a magnitude faster. For example, running 1,000 inserts in a single transaction ran 500 times faster (!) than 1000 individual transactions in one of our performance tests.
In greenDAO, use DaoSession.runInTx(Runnable) to make the given Runnable run as a transaction. If you have a list of entities of the same type, you can use the insertInTx or updateInTx methods of the DAO class belonging to the entity.
Why do my queries slow down when the database table grows?
The first think to check if you have an index matching the WHERE clause of your query.
Testing / Unit Testing
How to setup some tests involving greenDAO entities?
greenDAO already comes with a couple of base classes for unit testing and generates stubs for JUnit test classes. For the base classes, have a look at the (also part of greenDAO.jar). These test classes initialize an in-memory database and the greenDAO infrastructure (a DAO or DaoSession object). Also, it might be interesting to look at the , which is testing greenDAO itself. It makes extensive use of the base classes.
Troubleshooting
I am getting an SQLite error code, what does it mean?
Check SQLite’s result codes and extended result codes.