履歴テーブル、今回はこう作りました 〜 Delegated Types編 〜 / How We Built Our History Table This Time — With Delegated Types

Ruby on Railsのテーブル設計とトランザクション処理 LT Nightの資料です #techbaton_findy
https://findy.connpass.com/event/375098/

5分で背景含め様々を説明するのは無理だったので補足記事があります: https://moznion.hatenadiary.com/entry/2025/11/27/223512

1. ཤྺςʔϒϧɺࠓճ͸͜͏࡞Γ·ͨ͠  ʙ
   %FMFHBUFE
   5ZQFTฤ
   ʙ 3VCZ
   PO
   3BJMTͷςʔϒϧઃܭͱτϥϯβΫγϣϯॲཧ
   -5
   /JHIU
   5IV
   
   /PW
   
   !NP[OJPO
2.  4NBSU#BOL
   *OD
   
   4PGUXBSF
   &OHJOFFS 5BJLJ
   ,BXBLBNJ
   !NP[OJPO !NP[OJPO !NP[OJPO
3. 
4. ཤྺςʔϒϧ
5.  ཤྺςʔϒϧ ͦͷ໊ͷ௨ΓཤྺΛදݱɾอଘ͢ΔͨΊͷςʔϒϧ • Ϣʔβʔͷߦಈ • γεςϜͷߋ৽ • ͳͲͳͲ……
6.  ཤྺςʔϒϧ͕͋ΔͱԿ͕ྑ͍ͷ͔ w
   ໰୊͕ൃੜͨ࣌͠ʹௐ͕ࠪͰ͖Δ
   ྫ
   Ϣʔβʔ໰͍߹ΘͤରԠ
   w
   ূ੻ͱͯ͠ѻ͑Δ
   ྫ
   ؂ࠪରԠ
   w
   Ұ࿈ͷཤྺΛྲྀ͠ࠐΉ͜ͱͰ
   ࣌
   ܥྻͷॲཧ͕Ͱ͖Δ̈
   w
   ߦಈɾಈଶ෼ੳʹ࢖͑Δ
   w
   ͳͲͳͲʜʜ ̈ҰछͷΠϕϯτιʔγϯά
7.  ཤྺςʔϒϧ͕͋ΔͱԿ͕ྑ͍ͷ͔ ཤྺΛImmutableͳσʔλͱͯ͠ѻ͏͜ͱʹΑΓ
 ͜ͷΑ͏ͳϝϦοτΛಘΔ͜ͱ͕Ͱ͖Δ w
   ໰୊͕ൃੜͨ࣌͠ʹௐ͕ࠪͰ͖Δ
   ྫ
   Ϣʔβʔ໰͍߹ΘͤରԠ
   w
   ূ੻ͱͯ͠ѻ͑Δ
   ྫ
   ؂ࠪରԠ
   w
   Ұ࿈ͷཤྺΛྲྀ͠ࠐΉ͜ͱͰ
   ࣌
   ܥྻͷॲཧ͕Ͱ͖Δ̈
   w
   ߦಈɾಈଶ෼ੳʹ࢖͑Δ
   w
   ͳͲͳͲʜʜ ̈ҰछͷΠϕϯτιʔγϯά
8. ࠓճͷࣄྫ
   ΞϑΟϦΤΠτϓϩάϥϜ
9.  ΞϑΟϦΤΠτϓϩάϥϜ֓؍ ΞϑΟϦΤΠτϓϩάϥϜࢀՃ
10.  ΞϑΟϦΤΠτϓϩάϥϜ֓؍ ΞϑΟϦΤΠτϓϩάϥϜࢀՃ ֎෦αΠτ ίϯόʔδϣϯ
11.  ΞϑΟϦΤΠτϓϩάϥϜ֓؍ ΞϑΟϦΤΠτϓϩάϥϜࢀՃ ֎෦αΠτ ίϯόʔδϣϯ ৘ใಉظ "41̈ ̈"41
    ΞϑΟϦΤΠταʔϏεϓϩόΠμʔ
12.  ΞϑΟϦΤΠτϓϩάϥϜ֓؍ ΞϑΟϦΤΠτϓϩάϥϜࢀՃ ֎෦αΠτ ίϯόʔδϣϯ ৘ใಉظ "41̈ ঢ়ଶΛ௨஌
 (ൃੜɾঝೝɾغ٫) ̈"41
    ΞϑΟϦΤΠταʔϏεϓϩόΠμʔ
13.  ΞϑΟϦΤΠτϓϩάϥϜ֓؍ ΞϑΟϦΤΠτϓϩάϥϜࢀՃ ֎෦αΠτ ίϯόʔδϣϯ ৘ใಉظ "41̈ ঢ়ଶΛ௨஌
 (ൃੜɾঝೝɾغ٫) ̈"41
    ΞϑΟϦΤΠταʔϏεϓϩόΠμʔ ͜ΕΒͷΠϕϯτΛཤྺςʔϒϧͰѻ͏
14.  ΞϑΟϦΤΠτϓϩάϥϜ֓؍ ΞϑΟϦΤΠτϓϩάϥϜࢀՃ ֎෦αΠτ ίϯόʔδϣϯ ৘ใಉظ "41̈ ঢ়ଶΛ௨஌
 (ൃੜɾঝೝɾغ٫) ̈"41
    ΞϑΟϦΤΠταʔϏεϓϩόΠμʔ ͜ΕΒͷΠϕϯτΛཤྺςʔϒϧͰѻ͏ ͜ͷϥΠϑαΠΫϧதͰҰҙͳID΋ඞཁ
15.  σʔλϞσϦϯά
    ʙࠓճ͸͜͏࡞Γ·ͨ͠ʙ
    .Z42-Ͱ͢
16.  ཤྺςʔϒϧσʔλϞσϦϯά DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU
17.  ཤྺςʔϒϧσʔλϞσϦϯά DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU ͢΂ͯͷϨίʔυ͸௥هΦϯϦʔ (immutable) DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
18.  ཤྺςʔϒϧσʔλϞσϦϯά DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU ͜ͷID͕ϥΠϑαΠΫϧதͰҰҙʹͳΔ DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
19.  τϥϯβΫγϣϯڥք DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
20.  DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU ϢʔβʔͷΞΫγϣϯʹΑΓൃੜ
21.  τϥϯβΫγϣϯڥք DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU ίϯόʔδϣϯ͢ΔͱASP͔Β௨஌͞ΕΔ (εςʔτϚγϯత)
22.  τϥϯβΫγϣϯڥք DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU ASP͔Βͷ௨஌ΛϩΪϯά (ௐࠪ౳ʹར༻Ͱ͖Δ)
23.  DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU ࢖͍΍͢͞
    
    ύϑΥʔϚϯεͷͨΊͷඇਖ਼نԽ DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
24.  DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU ࢖͍΍͢͞
    
    ύϑΥʔϚϯεͷͨΊͷඇਖ਼نԽ DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
25.  DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU ࢖͍΍͢͞
    
    ύϑΥʔϚϯεͷͨΊͷඇਖ਼نԽ DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
26.  %FMFHBUFE
    5ZQFT DPOWFSTJPO@FWFOU CJHJOU JE 1, CJHJOU DPOWFSTJPO@JE TUSJOH FWFOUBCMF@UZQF EFMFHBUFE
    UZQFT CJHJOU FWFOUBCMF@JE EFMFHBUFE
    UZQFT CJHJOU DPOWFSTJPO@FWFOU@QSPWJEFS@MPH@JE EBUBUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQMJDBUJPOT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU FOSPMMNFOU@JOUFOUT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', EBUFUJNF FOSPMMFE@BU DPOWFSTJPOT CJHJOU JE 1, CJHJOU VTFS@JE VTFST΁ͷ', CJHJOU P ff FS@JE P ff FST
    Ҋ݅
    ΁ͷ', CJHJOU FOSPMMNFOU@JOUFOU@JE FOSPMMNFOU@JOUFOUT΁ͷ', DPOWFSTJPO@FWFOU@SFKFDUJPOT CJHJOU JE 1, EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@BQQSPWBMT CJHJOU JE 1, JOUFHFS SFXBSE@BNPVOU JOUFHFS QVSDIBTF@BNPVOU EBUFUJNF PDDVSSFE@BU DPOWFSTJPO@FWFOU@QSPWJEFS@MPHT CJHJOU JE 1, TUSJOH QSPWJEFS@OBNF KTPO SBX@QBZMPBE EBUFUJNF SFDFJWFE@BU
27.  %FMFHBUFE
    5ZQFTʜʜͷલʹ45* ✅
    ͬ͘͟Γݴ͏ͱ
    %#ϨϕϧͰ͸ͭͷςʔϒϧʹϨίʔυΛอଘ͠εΩʔϚΛڞ༗ͭͭ͠
    ͦͷதͰෳ਺ͷNPEFMΫϥε
    ৼ෣͍
    ΛදݱՄೳͱ͢Δύλʔϯ ୯Ұςʔϒϧܧঝʢ45*
    4JOHMF
    5BCMF
    *OIFSJUBODFʣ͸ɺෳ਺ͷϞσϧΛ
    ୯ҰͷσʔλϕʔεςʔϒϧʹऩೲͰ͖Δ3BJMTͷύλʔϯͰ͢ɻ
    ͜Ε͸ɺ͞·͟·ͳΤϯςΟςΟʹڞ௨ͷଐੑ΍ৼΔ෣͍Λ࣋ͨͤͭͭɺ
    ΤϯςΟςΟݻ༗ͷৼΔ෣͍΋͍࣋ͨͤͨ৔߹ʹศརͰ͢ɻ
    IUUQTSBJMTHVJEFTKQBTTPDJBUJPO@CBTJDTIUNM୯ҰςʔϒϧܧঝʢTUJʣ
28.  %FMFHBUFE
    5ZQFT %FMFHBUFE
    UZQFTʢҕৡܕʣ͸ɺ୯Ұςʔϒϧܧঝʢ45*ʣʹΑΔ
    ςʔϒϧංେԽͷ໰୊ΛɺEFMFHBUFE@UZQFͰղܾ͠·͢ɻ
    ͜ͷΞϓϩʔνʹΑΓɺڞ༗ଐੑΛεʔύʔΫϥεͷςʔϒϧʹอଘ͠ɺ
    αϒΫϥεݻ༗ͷଐੑΛผͷςʔϒϧʹอଘͰ͖ΔΑ͏ʹͳΓ·͢ɻ
    IUUQTSBJMTHVJEFTKQBTTPDJBUJPO@CBTJDTIUNMEFMFHBUFEUZQFT ✅
    ͬ͘͟Γݴ͏ͱ
    %#ϨϕϧͰ͸ͭͷ਌ςʔϒϧʹڞ௨ͷϨίʔυΛอଘ͠ɺ
    ͦΕʹؔ࿈͢Δࢠςʔϒϧʹݻ༗ͷϨίʔυΛอଘ͠ɺ
    ݸผͷNPEFMΫϥε
    ৼ෣͍
    Λ࣮૷Մೳͱ͢Δύλʔϯɻ
29.  %FMFHBUFE
    5ZQFTΛ࢖͏͜ͱʹΑΔخ͠͞ • ֤छΠϕϯτΛݸผͷςʔϒϧ಺ʹอଘͰ͖Δ • ڞ௨ͷॲཧ͸਌ςʔϒϧɺݻ༗ͷΧϥϜ΍ॲཧ͸ݸผςʔϒϧͷ
 ੹຿ʹͰ͖Δ̈
    •
    ݸผςʔϒϧ΁ͷΫΤϦͰ׬݁ͤ͞Δ͜ͱ͕Ͱ͖Δ̈̈ • ಛఆͷΫϥε (ςʔϒϧ) ͔͠ඥ෇͔ͳ͍͜ͱ͕อূͰ͖ΔͷͰ
 σʔλߏ଄ͱͯ͠ഁ୼ͤ͞ʹ͍͘ ̈45*ͩͱݻ༗ͷΧϥϜΛ࣋ͨͤΔ͜ͱ͸ਪ঑͞Εͳ͍
    ̈̈45*ͩͱ౷ҰςʔϒϧʹΫΤϦ͢Δඞཁ͕ग़ͯ͘ΔͨΊɺڊେςʔϒϧʹͳΔͱ໰୊͕ग़ΔՄೳੑ͕͋Δ
30.  %FMFHBUFE
    5ZQFTΛ࢖͏͜ͱʹΑΔ໘౗͞ • JOIN͕૿͑ΔͷͰύϑΥʔϚϯε͕ಡΈʹ͍͘ • ಛʹෳࡶͳΫΤϦʹͳΔͱ…… • Railsݻ༗ͷػೳɾ֓೦Ͱ͋ΔͷͰ̈
    SQL౳ͱͷ࿈ܞʹϋʔυϧ͕͋Δ ̈Ή͠Ζ3BJMT͕ં֯ఏڙͯ͘͠Ε͍ͯΔػೳͳͷ͔ͩΒ͋Γ͕͍ͨͱ͍͏ݟํ΋͋Δ
31.  ࠓճಘΒΕͳ͔ͬͨ%FMFHBUFE
    5ZQFTͷྑ͞ 1ͭͷςʔϒϧ͕ڊେʹͳΔ͜ͱΛ๷͛Δͱ͍͏ར఺͕͋Δ͕…… => ࠓճ͸conversion_eventςʔϒϧ͕֤delegated typesͷ
 ςʔϒϧΛ౷΂͍ͯΔͷͰ௚઀తͳղܾ͕Ͱ͖ͣ
32. ؆୯·ͱΊ
33.  ؆୯·ͱΊ • ΠϛϡʔλϒϧσʔλͷԸܙΛड͚ͨཤྺςʔϒϧ͸ศར • Delegated TypesͰ֤ΠϕϯτΛදݱͯ͠ཤྺΛදݱ͢Δͱ
 ॊೈ͞ͱݎ࿚͞Λόϥϯεྑ͘औΓࠐΊͯྑ͍ • Έͳ͞Μ͸Ͳ͏ཤྺςʔϒϧΛ࡞͍ͬͯ·͔͢ʁ
34. མึर͍
    ͕࣌ؒ͋Ε͹
35.  3BJMTͷNPEFMʹSFMBUJPOΛுͬͯຬ଍ͯ͠͠·͏໰୊
    %FMFHBUFE
    5ZQFTʹݶΒͣ
    
    w 3BJMTΞϓϦͰด͡ΔͿΜʹ͸ྑ͍ҰํͰ42-͕ෳࡶʹͳΓ͕ͪ̈
    w %8)্ͰΫΤϦ͠Α͏ͱ͢ΔͱେมʹͳΔ܏޲̈̈
    ཤྺςʔϒϧ͸ͦͷಛੑ্ɺ෼ੳΫΤϦ͕ൃߦ͞ΕΔ܏޲͕͋ΔͷͰ
    42-΋૊Έқ͘ͳ͍ͬͯΔͱྑͦ͞͏̈̈̈ ̈Ӆṭ͞Ε͍ͯΔ͚ͩͱ͍͏ͷ͸ͦ͏ʜʜ
    ̈̈%FMFHBUFE
    5ZQFTͷ֤UZQFͱJEͷϖΞΛΫΤϦʹຒΊࠐΉඞཁ͕͋Δͱ͔
    ̈̈̈ద੾ʹਖ਼نԽΛ่͢ͳͲ 3BJMTͷNPEFMϦον͗͢໰୊
36.   AFOSPMMNFOU@JOUFOU@JEA
    Ͱ
    ADPOWFSTJPOTA
    ΛҾ͘
     ADPOWFSTJPO@FWFOUTA
    UBCMFͱ+0*/
    
    APDDVSSFE@BUA
    Λ%&4$Ͱιʔτ͠ɺ݅औಘ
    ߋʹऔಘͨ͠Ϩίʔυͷ
    AFWFOUBCMFA
    ʹΞΫηε͢Δ͜ͱͰ
    ݸผͷΠϕϯτΛऔಘ͢Δ͜ͱ͕Ͱ͖Δ̈ ɻ
    ̈ΫΤϦ͕ൃʹͳͬͯ͠·͏ͱ͜Ζ͕τϨʔυΦϑ ࠷৽ͷΠϕϯτΛͲ͏Ҿ͔͘ 💡 ͜ͷ࣌ `eventable_application?` ΍ `eventable_rejection?` ͷΑ͏ͳɺ
 `delegated type` ͕ੜ΍͢ϝιουΛ࢖͏ͱछผͷ൑ఆ͕Ͱ͖ͯศར
37.  ImmutableͳσʔλͰ͋ΔͷͰϨίʔυ਺͸جຊతʹ૿͑ଓ͚ΔҰํ
 => ৔߹ʹΑΓσʔλΛ෼ׂ͢Δඞཁ͕͋Δ • ਫฏγϟʔσΟϯά • ݹ͍σʔλΛDB͔ΒDWHͳͲʹ௥͍ग़̈͢ ̈࣌ܥྻσʔλͰ͋Ε͹ݹ͍σʔλ͸͋·ΓΞΫηε͞Εͳ͍܏޲ʹ͋Δ͔΋͠Εͳ͍ɺͱ͍͏Ծઆ σʔλͷංେԽ΁ͷରԠ