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@ -1006,29 +1006,30 @@
- The instances of a potential subclass participate in a relationship unique to that subclass.
- DONE Block 3
- DONE DB transaction management
- anomalies
- DONE ACID (Atomicity, Consistency, Isolation, Durability): A set of properties that guarantee the reliability and integrity of database transactions. #flashcard
- Atomicity: :-> The property that ensures a transaction is treated as a single, indivisible unit of work. It either executes all its operations successfully or rolls back to the initial state if any operation fails.
- Consistency: :-> The property that ensures a transaction transforms the database from one consistent state to another consistent state. It maintains data integrity and adheres to defined business rules.
- Isolation: :-> The property that ensures concurrent transactions do not interfere with each other. Each transaction operates in isolation until it completes, preventing interference or conflicts.
- Durability: :-> The property that ensures committed changes made by a transaction are permanently saved and will survive any subsequent system failures or crashes.
- DONE Concurrency control
- DONE Meaning of serialisability.
- DONE How locking can ensure serialisability.
- Locking achieves serializability by using locks to control access to
shared resources (e.g., database objects like tables or rows) and
prevent conflicts between concurrent transactions.
- DONE 2PL
- In the 2PL protocol, transactions acquire and release locks on database
objects (e.g., tables, rows) in two distinct phases: the growing phase
and the shrinking phase.
- DONE Deadlock and how it can be resolved.
- LATER anomalies
- DONE Deadlock and how it can be resolved. #flashcard
- A deadlock is a situation in which two or more transactions are unable
to proceed because each is waiting for a resource held by the other,
resulting in a circular dependency and a system halt. It is a form of
resource contention that can occur in concurrent systems, including
database management systems.
- DONE How timestamping can ensure serialisability.
- DONE ACID (Atomicity, Consistency, Isolation, Durability): A set of properties that guarantee the reliability and integrity of database transactions. #flashcard
collapsed:: true
- Atomicity: :-> The property that ensures a transaction is treated as a single, indivisible unit of work. It either executes all its operations successfully or rolls back to the initial state if any operation fails.
- Consistency: :-> The property that ensures a transaction transforms the database from one consistent state to another consistent state. It maintains data integrity and adheres to defined business rules.
- Isolation: :-> The property that ensures concurrent transactions do not interfere with each other. Each transaction operates in isolation until it completes, preventing interference or conflicts.
- Durability: :-> The property that ensures committed changes made by a transaction are permanently saved and will survive any subsequent system failures or crashes.
- DONE Concurrency control
- LATER Meaning of serialisability.
- DONE How locking can ensure serialisability. #flashcard
- Locking achieves serializability by using locks to control access to
shared resources (e.g., database objects like tables or rows) and
prevent conflicts between concurrent transactions.
- DONE 2PL #flashcard
- In the 2PL protocol, transactions acquire and release locks on database
objects (e.g., tables, rows) in two distinct phases: the growing phase
and the shrinking phase.
- DONE How timestamping can ensure serialisability. #flashcard
- By using transaction timestamps and enforcing the read and write
validation checks, concurrency control mechanisms can ensure that
transactions are executed in a way that maintains data consistency and
@ -1049,7 +1050,7 @@
- Checkpoint records.
- Often used for other purposes (for example, auditing).
- For autiding
- DONE Purpose of checkpointing.
- DONE Purpose of checkpointing. #flashcard
- When failure occurs, redo all transactions that
committed since the checkpoint and undo all
transactions active at time of crash.