Four Major Database Research Areas

Data Models
A representation, usually graphic, of a complex “real-world” data structure.

Database Languages
Database languages, compared with general-purpose languages, have only a limited expressive power. The DBMS query language can be embedded in a general-purpose language which ensures full computational power.

Transactions Control
A transaction is a logical unit of work; that is, it must be entirely completed or aborted—no intermediate ending states are accepted. All transactions must have the following properties:
  1. Atomicity requires that, unless all operations (parts) of a transaction are completed, the transaction is aborted.

  2. Durability assures that, once a transaction is completed, the database reaches a consistent state; that state can not be lost, even in the event of a system failure.

  3. Serializability ensures that the selected order of transaction operations creates a final database state that would have been produced if the transactions are executed in a serial fashion.

  4. Isolation assures that data used during the execution of a transaction can not be used by a second transaction until the first one is completed.
†Concurrency control is a DBMS feature that is used to coordinate the simultaneous execution of transactions in a multiprocessing database system while preserving data integrity.

Data Structures
An integral component of the database system is a secondary storage management facility, which mostly uses B-trees.

Review: Transaction Control
    Which is NOT one of the properties of transactions?

      Atomicity
      Durability
      Scalability
      Serializability
        Result:




      Chris is asleep after burning the midnight oil (awake all night)    
      trying to finish his article.