SELECT * FROM Kotlin - Droidcon NYC 2019

Now that Kotlin is the preferred language of Android developers, what is the best library to work with SQLite databases using Kotlin? Room just released support for Kotlin Coroutines, and SqlDelight released support for Kotlin Multi-platform. Room has great documentation and hides a lot of implementation detail, while SqlDelight lets you write raw SQL statements with an Android Studio plugin and then generates type-safe code for you. In this session, you'll see a rundown of these two libraries, along with live coding demos to help you decide which library sounds right for you in this Kotlin world.

Transcript

1. SELECT * FROM Kotlin
   @HandstandSam
   Sam Edwards
   Lead Android Engineer @ Capital One
   

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2. @ H A N D S TA N D S A M # D C N Y C 1 9
   WARNING: These slides were not meant to be standalone,
   but I wanted to share them.
   This talk heavily switches between Android Studio, Emulator and Chrome. Every
   time you see it means that I switched over and showed
   something else. The files are in https://github.com/handstandsam/ShoppingApp.
   The video will be better to watch when it is out, but it’s not published at this time.
   E X P O RT E D S L I D E S WA R N I N G
   Filename.kt
   

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3. # D C N Y C 1 9
   @ H A N D S TA N D S A M
   Why Are We Talking About This Today?
   ! Kotlin for over 2 years and LOVE it
   ! Needed to evaluate databases ORMs
   ! Submitted this talk… and it got accepted
   ! So… I went a little overboard and decided to dive in heads first
   

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4. !
   

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5. !
   

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6. # D C N Y C 1 9
   @ H A N D S TA N D S A M
   Coding Brings Confidence
   

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7. # D C N Y C 1 9
   @ H A N D S TA N D S A M
   Sharing Brings Confidence
   

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8. @ H A N D S TA N D S A M # D C N Y C 1 9
   B E G I N N E R E X P E RT
   

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9. @ H A N D S TA N D S A M # D C N Y C 1 9
   B E G I N N E R E X P E RT
   

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10. @ H A N D S TA N D S A M # D C N Y C 1 9
    B E G I N N E R E X P E RT
    

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11. @ H A N D S TA N D S A M # D C N Y C 1 9
    B E G I N N E R E X P E RT
    

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12. @ H A N D S TA N D S A M # D C N Y C 1 9
    B E G I N N E R E X P E RT
    

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13. @ H A N D S TA N D S A M # D C N Y C 1 9
    B E G I N N E R E X P E RT
    

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14. !
    

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15. Pair Programming
    

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16. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Shopping App on GitHub
    github.com/handstandsam/ShoppingApp
    

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17. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Shopping App on GitHub
    github.com/handstandsam/ShoppingApp
    Shopping App!
    

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18. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Our Task at Hand
    ! Make our Shopping Cart functionality persist between
    sessions as it should increase sales $$$
    ! Our codebase has no database currently
    

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19. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    In-Memory Version
    ! Use an In-Memory Version (No database, but can test functionality)
    ! Create Interfaces to allow for swapping of DB implementations
    ! Create a reactive stream that be subscribed to for updates
    

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20. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    In-Memory Version
    ! Use an In-Memory Version (No database, but can test functionality)
    ! Create Interfaces to allow for swapping of DB implementations
    ! Create a reactive stream that be subscribed to for updates
    ShoppingCartDao.kt & InMemoryShoppingCartDao.kt
    

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21. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    What Library Should We Use?
    Room
    SQLDelight
    

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22. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    What Library Should We Use?
    Room
    SQLDelight
    Do We NEED a Local Database?
    

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23. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Do We NEED a Local Database?
    ! Shared Preferences?
    ! Local JSON File
    ! On the Server?
    

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24. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    With Great Power Comes Great Responsibility
    ! You are responsible for every byte of data you persist
    ! Any writes you make will need to be supported during any upgrade
    ! Migrations can be used to modify data structure
    

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25. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Reactive Stream for UI Updates
    ! Shopping Cart reflect the most recent changes to the data.
    ! Options
    ! Register a Listener or a callback to our datastore
    ! RxJava - Flowable
    ! Android Architecture Components - LiveData
    ! Kotlin Coroutines - Channels or Flow
    

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26. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Reactive Stream for UI Updates
    ! Shopping Cart reflect the most recent changes to the data.
    ! Options
    ! Register a Listener or a callback to our datastore
    ! RxJava - Flowable
    ! Android Architecture Components - LiveData
    ! Kotlin Coroutines - Channels or Flow
    ShoppingCart.kt
    

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27. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Unit Tests
    ! Validate our current implementation
    ! Give confidence in our code
    

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28. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Unit Tests
    ! Validate our current implementation
    ! Give confidence in our code
    ShoppingCartInMemoryTest.kt
    

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29. Our Technical Requirements
    

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30. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Our Technical Requirements
    ! Use a stable, proven version of a library
    ! Don’t break incremental builds
    ! Publish database changes reactively
    ! Make sure you separate code in modules:
    ! shopping-cart
    ! shopping-cart-sqldelight
    ! shopping-cart-room
    

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31. Evaluating Database Libraries
    

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32. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    SQLDelight
    Evaluating Database Libraries
    

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33. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    ! Amazing online documentation
    ! Proven and written by Google
    ! Code Generation via Annotation Processing
    (kapt) breaks incremental builds. (Compiler
    option, off by default until stable)
    ! It’s last stable release was June 13 with 2.1.0, but
    2.2.0-beta01 just came out on August 22
    Room (JetPack Library)
    

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34. Room
    

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35. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Setup
    ! Gradle implementation Dependencies (For Runtime Logic)
    ! Gradle kapt Dependencies (For Annotation Processing)
    

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36. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Setup
    ! Gradle implementation Dependencies (For Runtime Logic)
    ! Gradle kapt Dependencies (For Annotation Processing)
    build.gradle
    

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37. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    ! Needed: Entity, Dao, Database
    Written Code for Room
    RoomItemInCartEntity
    RoomItemInCartDao
    RoomItemInCartDatabase
    

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38. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room Generated Code
    RoomItemInCartDao_Impl
    RoomItemInCartDatabase_Impl
    

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39. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Generated Code from Annotations is
    ! Annotations @Entity, @Dao, @Query(“…”)
    ! Deterministic generated code
    ! Can break incremental builds
    

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40. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Using Room in Shopping App
    SessionGraph.kt
    

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41. Validation/Introspection/Debugging
    

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42. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    I ❤ Debugging Features
    

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43. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Android Debug Database
    

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44. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Android Debug Database
    ! https://github.com/amitshekhariitbhu/Android-Debug-Database
    ! debugImplementation 'com.amitshekhar.android:debug-db:1.0.6'
    ! Custom Port Config, forwarded from Emulator:
    ! debug { resValue("string", "PORT_NUMBER", “8081") }
    ! adb forward tcp:8081 tcp:8081
    ! http://localhost:8081
    ! Image: https://www.todayifoundout.com/wp-content/uploads/2017/11/rick-
    astley.png
    

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45. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Testing Room
    ! Unit test must run on an Android device
    ! https://developer.android.com/training/data-storage/room/testing-db
    ! Can be run without UI
    ! ./gradlew shopping-cart-room:connectedAndroidTest --parallel
    

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46. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Testing Room
    ! Unit test must run on an Android device
    ! https://developer.android.com/training/data-storage/room/testing-db
    ! Can be run without UI, so runs fast
    ! ./gradlew shopping-cart-room:connectedAndroidTest --parallel
    RoomShoppingCartTest.kt
    

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47. SQLDelight
    

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48. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    ! Generates Kotlin code as of v1.0.0
    ! Is a stable release
    ! Does incremental code generation from
    SQL files, without using annotations (kapt)
    ! Supports Kotlin Multiplatform
    SQLDelight (Written by Square)
    

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49. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    SQLDelight
    ! Setup
    ! Gradle Plugin (To Perform Code Generation)
    ! Gradle implementation Dependencies (For Runtime Logic)
    

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50. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    SQLDelight
    ! Setup
    ! Gradle Plugin (To Perform Code Generation)
    ! Gradle implementation Dependencies (For Runtime Logic)
    build.gradle
    

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51. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Written SQL for SQLDelight
    ItemInCartEntity.sq
    

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52. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    SQLDelight Code Generation
    ! Leverages Gradle Plugin
    ! Detects changes in the .sq files and will regenerate if needed
    ! Provides incremental builds
    

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53. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    ItemInCart.kt
    ItemInCartEntityQueries.kt

    DatabaseImpl.kt
    Generated Code for SQLDelight
    

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54. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Running SQLDelight
    SessionGraph.kt
    

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55. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Showing SQLDelight Works
    Android Debug Database
    

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56. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Unit Testing
    ! JVM Driver allowing it to run on the JVM without any Android dependencies.
    ! Fast TDD development
    ! ./gradlew shopping-cart-sqldelight:testDebug
    

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57. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Unit Testing
    ! JVM Driver allowing it to run on the JVM without any Android dependencies.
    ! Fast TDD development
    ! ./gradlew shopping-cart-sqldelight:testDebug
    SqlDelightShoppingCartTestDelegate.kt
    

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58. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Kotlin Multiplatform
    ! https://github.com/square/sqldelight/tree/master/sample
    ! Android
    ! iOS
    

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59. There Is No Magic
    

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60. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    AndroidX SupportSQLiteDatabase
    ! “A database abstraction which removes the framework dependency and
    allows swapping underlying sql versions. It mimics the behavior
    of SQLiteDatabase”
    ! https://developer.android.com/reference/androidx/sqlite/db/
    SupportSQLiteDatabase
    

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61. @ H A N D S TA N D S A M # D C N Y C 1 9
    

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62. @ H A N D S TA N D S A M # D C N Y C 1 9
    

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63. @ H A N D S TA N D S A M # D C N Y C 1 9
    SQLDelight
    Room
    

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64. @ H A N D S TA N D S A M # D C N Y C 1 9
    SQLDelight
    Room
    

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65. @ H A N D S TA N D S A M # D C N Y C 1 9
    SQLDelight
    

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66. And The Winner Is…
    

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67. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    https://handstandsam.com/2019/03/10/it-depends-is-the-answer-to-your-android-question/
    

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68. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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69. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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70. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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71. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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72. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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73. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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74. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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75. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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76. # D C N Y C 1 9
    @ H A N D S TA N D S A M
    Room
    ! Uses SupportSQLiteDatabase
    ! Maintained by Google
    ! Write some SQL in Annotations
    ! KAPT Annotation Processing
    ! Great Documentation
    ! Hard to read generated code
    ! Tried and Tested
    ! Requires testing on Device
    SQLDelight
    ! Uses SupportSQLiteDatabase
    ! Maintained by Square
    ! Write your own SQL
    ! Code Generation from SQL
    ! Not Great Android Documentation
    ! Super clean generated code
    ! Not widely adopted (yet)
    ! JVM Unit Tests
    

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77. THE END
    

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