# Quiz

+ What is the correct implement of TiDB database transactions? (Select 2)
  + `A` . TiDB database optimistic locking do not require lock information to be written in the Lock family
  + `B` . The.Write column family records transaction commit information, or version information
  + `C` . Pessimistic lock down, we need to mention the prewrite phase to the DML operation
  + `D` . Optimistic locking, the transaction detects write and lock conflicts in the prewrite phase

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B, D