Android/ORMLite Insert Row with ID

Question

I'm currently using ORMLite to work with a SQLite database on Android. As part of this I am downloading a bunch of data from a backend server and I'd like to have this data added to the SQLite database in the exact same format it is on the backend server (ie the IDs are the same, etc).

So, my question to you is if I populate my database entry object (we'll call it Equipment), including Equipment's generatedId/primary key field via setId(), and I then run a DAO.create() with that Equipment entry will that ID be saved correctly? I tried it this way and it seems to me that this was not the case. If that is the case I will try again and look for other problems, but with the first few passes over the code I was not able to find one. So essentially, if I call DAO.create() on a database object with an ID set will that ID be sent to the database and if it is not, how can I insert a row with a primary key value already filled out?

Thanks!

Answer 1

@Femi is correct that an object can either be a generated-id or an id, but not both. The issue is more than how ORMLite stores the object but it also has to match the schema that the database was generated with.

ORMLite supports a allowGeneratedIdInsert=true option to @DatabaseField annotation that allows this behavior. This is not supported by some database types (Derby for example) but works under Android/SQLite.

For posterity, you can also create 2 objects that share the same table -- one with a generated-id and one without. Then you can insert using the generated-id Dao to get that behavior and the other Dao to take the id value set by the caller. Here's another answer talking about that. The issue for you sounds like that this will create a lot of of extra DAOs.

The only other solution is to not use the id for your purposes. Let the database generate the id and then have an additional field that you use that is set externally for your purposes. Forcing the database-id in certain circumstances seems to me to be a bad pattern.

Answer 2

From http://ormlite.com/docs/generated-id:

Boolean whether the field is an auto-generated id field. Default is false. Only one field can have this set in a class. This tells the database to auto-generate a corresponding id for every row inserted. When an object with a generated-id is created using the Dao.create() method, the database will generate an id for the row which will be returned and set in the object by the create method. Some databases require sequences for generated ids in which case the sequence name will be auto-generated. To specify the name of the sequence use generatedIdSequence. Only one of this, id, and generatedIdSequence can be specified.

You must use either generatedId (in which case it appears all ids must be generated) or id (in which case you can set them) but not both.