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Concurrency Control, Serializability - Coggle Diagram

- - - - Shrinking phase
      - Growing phase
      - Rules
        
        Two transactions cannot have conflicting locks
        
        No unlock operation can precede a lock operation in the same transaction
        
        No data are affected until all locks are obtained
    - - Occurs when two or more transactions wait for each other to unlock data. Called deadly embrace. Circular
      - Control Techniques
        
        Deadlock prevention
        
        Deadlock detection (Time stamping - each come at a different time)
        
        Deadlock avoidance
      - The Dining Philosophers
        
        5 Philosphers. Central dining room but 5 bedrooms. Each had a gold fork but two forks could pick up the spaghetti. Realised no one person could use one fork, they waited for someone to drop their fork.