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DB Transactions by Junior SE G1, Type of backups, (Aborted, Patially…
DB Transactions by Junior SE G1
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Deadlocks
Deadlock avoidance
Deadlock detection and recovery
Deadlock prevention
3 SQL transaction statements
BEGIN
Begin the transaction
COMMIT
If no error occurs
ROLLBACK
If an error occurs
Atomic Operations :
:star: You never get half an operation :
:warning: Operations may not work because:
Violation of constraints
Datatype mismatch
Syntax error
:pencil2: If an error occurs, entire transaction is undone. (ROLLBACK;)
:check: keeps databases in a consistent state, that moves forward in time.
Auto Commit Mode
Databases are by default on an auto commit mode
Auto mode can be turned off
In a non AutoCommitMode You need to type "commit" to save the new changes in your DB
Before commiting, you can type "rollback" to undo all the changes you have done
ACID properties
Atomic
Isolated
States
RDBMS
Oracle, MS SQL Server, IBM DB2, PostgreSQL, MySQL
Type of backups
Backups :check:
immediate backup
archival backup
backups of the logs file
incremental backup
incremental backup copy of modification made since the last complete or incremental backup
Aborted
Patially commited
Commited
Active
Deadlock
Detection
Detection and recovery
Prevention
scheduler: concurrency control
Serial execution
parallel execution
Transaction manager : ensures that transactions will not violate integrity constraints
Recovery manage: restore the databse
Breaking
Detection and recovery
Transaction management