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DBFlow ORM library
Željko Plesac Android talks #10
Scope
• Intro
• Basic functions
• Advanced functions
• Benchmark tests
• Conclusion
Intro• debugging SQL errors is not easy
• Java ORM libraries
• problems with porting ORM to Android
• slow
• complex
• missing functionalities
Intro(2)
• DBFlow
• open source library, developed by Andrew Grosner (Raizlabs)
• current stable version is 1.7.0
• available at https://github.com/Raizlabs/DBFlow
Intro(3)
• DBFlow
• Built on maximum performance using annotation processing and lazy-loading
• based on Active Android, Schematic, Ollie, and Sprinkles
• Every feature has been unit tested
Basic functions
Including in your project
root Gradle file
Including in your project
With Griddle
Without Griddle
Including in your project
Init & destroy FlowManager in Application class
Database configuration
Multi database support you can define more than one DB
Model creation(1)
Model creation rules• All Models MUST HAVE A DEFAULT CONSTRUCTOR
• Subclassing works as one would expect: the library gathers all inherited fields annotated with @Column and count those as rows in the current class's database.
• Column names default to the field name as a convenience
• All fields must be public or package private as the ModelAdapter class needs access to them.
• All model class definitions must be top-level (in their own file) and public or package private
Foreign key
columnName name of column in this table
columnType type of column in this table (must be same)
foreignKeyName name of this column in referenced table
Foreign key - lazy installation
Foreign key
• whenever the current table is saved, the foreign key object is saved
• for maximum performance gain, set saveForeignKeyModel() property on false - you’ll have to manage it yourself
Basic SQL queries
• DBFlow provides 2 ways for SQL Queries
• using wrapper classes
• using Transactions -> PREFERED
Basic SQL queries
• main difference is that wrapper classes are executed on current thread, while transaction uses TransactionQueue which has major effect on performance
• both can be used in sync or async mode
• callbacks are always called on UI thread
Wrapper classes
• quite similar to ActiveAndroid
• also can use TransactionQueue - DBFlow allows you to use library however you prefer (probably not good)
SELECT
UPDATE
DELETE
Other• Join statements
• order by
• having
• group by
• limit
• offset
Transactions
• utilises DBTransactionQueue, which is based on VolleyRequestQueue by using a PriorityBlockingQueue
• This queue will order our database transactions by priority (highest to lowest)
• 4 priorities - UI, HIGH, NORMAL, LOW
Transactions
Transactions• each transaction is described with ProccessModelInfo object
• name
• priority
• models
• For massive save() operations, use DBBatchSaveQueue - this will run a batch DBTransaction once the queue is full (default is 50 transactions)
• support for custom transactions
Advanced features
Observable models
Listen for changeson Model
create one observer and add as many
listeners as you want
Migrations
Migrations(2)
• don’t forget to increment your DB version!
Triggers
Indexes
More• Content providers - leverages DBFlow power
• Model caching
• Kotlin support
• prepackaged databases
• Model views
• and much more!!!
Benchmark tests
Benchmark tests• open source project, available at https://github.com/
Raizlabs/AndroidDatabaseLibraryComparison
• comparison between ActiveAndroid, SugarORM, Sprinkles
• tests are done on 25 000 records
• more on http://www.raizlabs.com/dev/2015/02/go-dbflow-fastest-android-orm-database-library/
Load
Save
Conclusion
Conclusion• IMHO currently the best ORM library
• large number of functionalities, every new version of library adds a few more
• active community
• complex documentation (currently no working example)
• steep learning curve
