トランザクションの基本概念

1.     


  (Transaction)               ,        ,     ,            .         SQL  ,      SQL  .       , A    1000    B  ,   A    1000   1000   B      ,   A    1000    B    1000   ,   A    1000    B    1000  ,          ,      .         ,     SQL              .


 SQL   ,        :BEGIN TRANSACTION,COMMIT,ROLLBACK.                ,DBMS           .   BEGIN TRANSACTION    , COMMIT ROLLBACK    .COMMIT      ,        .ROLLBACK    ,             ,      ,             ,         .


2.     


        :   (Atomicity),   (Consistency),   (Isolation)     (Durability).   ACID  .


(1)    


             ,        ,         .              ,     .


(2)    


                              .                   ,           .              ,             ,                       ,             .


(3)    


                .                           ,                 .


(4)    


         ,                   .                         .


    ACID            .  ACID            :


(1)          ,           .


(2)              .


       ,                               ;       ,                                  .                        .