enumeration - lock Types of Lock: Binary lock,...

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We can pass parameters to procedures in three ways. 1) IN-parameters 2) OUT-parameters 3) IN OUT-parameters Database design strategies classic approaches: Top-down, bottom-up Database design philosophies: Centralized, Decentralized Transaction Properties: Atomicity, Consistency, Isolation, Durability, Serializability , the sequence must continue through all succeeding statements until one of the following occurs: 1. A COMMIT statement is reached. Changes are permanently recorded within the database. 2. A ROLLBACK statement is reached. All changes are aborted and the database is returned to the previous consistent state. 3. The end of the program is successfully reached. This should be equivalent to a COMMIT. 4. The program is abnormally terminated. This should be equivalent to a ROLLBACK. Concurrency control aims to resolve: Lost Updates, Uncommited data, inconsistent retrievals Levels of lock: Database-level lock, Table level lock, Page Level lock, row level lock, field-level
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Unformatted text preview: lock Types of Lock: Binary lock, Shared/Exclusive locks Although locks prevent serious data inconsistencies, they can lead to two major problems: The resulting transaction may not be serializable The schedule may create deadlocks. A database deadlock is caused when two transactions wait for each other to unlock data. Two-phase locking consists of: Growing phase, Shrinking phase The three basic techniques to control deadlocks are: Deadlock Prevention, Deadlock detection, deadlock avoidance Time stamps must have two properties: Uniqueness, Monotonicity When using time stamps to manage concurrent transactions, there are two schemes that can be applied to decide which transaction is rolled back and which continues executing: WAIT/DIE , WOUND WAIT SCHEMES Levels of Backup Full backup, differential backup, transaction log backup Concepts that affect the recovery process: Write-ahead-log-protocol, Redundant transaction logs, Database buffers, database checkpoints....
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This note was uploaded on 08/30/2011 for the course COMPUTER computer taught by Professor Ms during the Spring '10 term at Oxford University.

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enumeration - lock Types of Lock: Binary lock,...

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