BUSI 3400 Lecture Notes - Lecture 10: Transaction Log, Serializability, Multiprocessing
30 Dec 2016
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Document Summary
Trigger a trigger is procedural sql code that is automatically executed by the dbms before or after a certain event occurs. Transaction any action that reads from and/or writes to a database. Coordination of simultaneous transaction execution in a multiprocessing. Uncommitted data accessed the uncommitted data occurs when one transaction is rolled back after another transaction has. Inconsistent retrievals can occur when a transaction uses aggregate functions while other transactions are updating data. Special dbms program establishes order of operations within which concurrent transactions are executed(serializability and isolation) Lock guarantees exclusive use of a data item to a current transaction. Transactions either completed or rolled back. stores database from a given state, usually inconsistent, to a previously. When a transaction updates data it actually updates the copy that is in the buffer. Later, buffers are written to the physical disk temporary storage in memory. Data is read from physical disk into buffers.
