Room2.1 DatabaseView あるある

Transcript

1. Room2.1 DatabaseView
   ͋Δ͋Δ
   ͋Δ͋ΔLTʙ ͓ਖ਼݄ͩΑʂAndroid & iOS߹ಉ େLTେձ ʙ Vol.10
   

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2. ࣗݾ঺հ
   • Koji Wakamiya
   • Studyplus, inc.
   • @koji-1009 (Github)
   • @D_R_1009 (Twitter, Hatena, etc…)
   
   

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3. DatabaseView ࢖ͬͯ·͔͢ʁ
   

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4. DatabaseViewʹ͍ͭͯʢ͓͞Β͍ʣ
   • Room 2.1Ͱ௥Ճ͞Εͨػೳ
   • Inner/Outer joinΛRoomͰ࣮ݱ
   • ςʔϒϧΛ͋Δ΂͖ܗʹ෼ׂ͠
   දࣔ(View)ʹ߹ΘͤͯσʔλΛ߹੒͢Δ͜ͱ͕Ͱ͖Δ
   
   

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5. ෳ਺ͷςʔϒϧͱForeignKey
   • ؔ࿈ͷ͋Δෳ਺ͷςʔϒϧΛѻ͏͜ͱʹͳΔͨΊ
   ForeignKeyΛར༻͢Δ͜ͱ͕͋Δ
   • ؔ࿈෇͚Λߦ͏͜ͱͰɺத৺ͱͳΔrowΛ࡟আͨ࣌͠ʹ
   ଞͷςʔϒϧͷrow΋࡟আ͢ΔͳͲͷߟྀΛߦ͏
   
   

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6. OnConflictStrategy.REPLACEͰ
   σʔλ͕ফ͑ͪΌ͏ࣄ݅
   

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7. OnConflictStrategy
   • InsetॲཧதʹConflict͕ൃੜ(row͕طʹଘࡏ)ͨ࣌͠
   ͲͷΑ͏ͳѻ͍Λ͢Δ͔ΛܾΊΔ͜ͱ͕Ͱ͖Δ
   • DBͷར༻༻్΍໨తʹ߹Θͤͯར༻͢ΔStrategy͕มΘΔ
   
   

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8. OnConflictStrategy
   • ABORT (default)
   • OnConflict strategy constant to abort the transaction.
   • REPLACE
   • OnConflict strategy constant to replace the old data and continue the
   transaction.
   • Ignore
   • OnConflict strategy constant to ignore the conflict.
   
   

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9. ࣄ݅ঢ়گ
   • ΞΠςϜςʔϒϧͱΞΠςϜฒͼॱςʔϒϧ͕ଘࡏ
   • ΞΠςϜ͸ΞϓϦىಈ࣌ʹαʔόʔͱಉظ
   • @InsertͱOnConflictStrategy.REPLACEͰશσʔλߋ৽
   • ฒͼॱͷσʔλ͸ΞϓϦ಺ʹ͔͠ଘࡏ͠ͳ͍ͨΊอ࣋
   
   

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10. ࣄ݅ঢ়گ
    • αʔόʔͱΞϓϦ಺DBΛಉظ(ϦϑϨογϡ)͢Δͱ
    ΞΠςϜϦετ͕දࣔ͞Εͳ͘ͳΔ
    • ௐ΂ͯΈΔͱʮΞΠςϜʯͷσʔλ͸͋Δ͕
    ʮΞΠςϜฒͼॱʯ͕ଘࡏ͠ͳ͘ͳ͍ͬͯΔ
    • Inner JoinͷͨΊDatabaseView͕ੜ੒͞Ε͍ͯͳ͍……ʁ
    
    

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11. Ͳ͏ͯ͠σʔλফ͑ͪΌ͏Μ……
    

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12. REPLACEʹΑΔUpdateॲཧ
    • REPLACE͸࣮࣭తʹUpdateॲཧʢͩͱࢥ͍ͬͯͨʣ
    • Conflictൃੜ͠ͳ͍ → ৽نrow࡞੒ॲཧ
    • Conflictൃੜ͢Δ → طଘrowߋ৽ॲཧ
    
    

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13. REPLACEʹΑΔUpdateॲཧ
    • REPLACE͸࣮࣭తʹUpdateॲཧʢͰ͸ͳ͍ʣ
    • Conflictൃੜ͠ͳ͍ → ৽نrow࡞੒ॲཧ
    • Conflictൃੜ͢Δ → طଘrowߋ৽ॲཧ
    طଘrow࡟আॲཧ + ৽نrow௥Ճॲཧ
    
    

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14. REPLACEʹΑΔUpdateॲཧ
    • طଘrowͷ࡟আ + ForeignKeyʹΑΔؔ࿈෇͚ʹΑΓ
    ʮΞΠςϜʯͷ࡟আͰʮΞΠςϜฒͼॱʯ͕࡟আ͞Ε͍ͯͨ
    • @InsertͰ͸ͳ͘@UpdateΛར༻͠ͳ͚Ε͹ͳΒͳ͔ͬͨ
    • ௥Ճͱߋ৽ॲཧΛϝιουͰ੾Γ෼͚Δ͜ͱͰ
    ͜ͱͳ͖ΛಘΔ͜ͱ͕Ͱ͖ͨ
    
    

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15. υΩϡϝϯτ͸ͪΌΜͱಡΉ
    ʢ͋ͱɺԣண͠ͳ͍ʣ
    

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16. Thanks!
    

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