From 86db38df5be4ffa178610a1484f81598922db559 Mon Sep 17 00:00:00 2001 From: Ryan Date: Wed, 14 Jun 2023 19:25:45 +0800 Subject: [PATCH] Auto saved by Logseq --- pages/总复习2023t1.md | 35 ++++++++++++++++------------------- 1 file changed, 16 insertions(+), 19 deletions(-) diff --git a/pages/总复习2023t1.md b/pages/总复习2023t1.md index 87205ff..b813b1e 100644 --- a/pages/总复习2023t1.md +++ b/pages/总复习2023t1.md @@ -1005,25 +1005,21 @@ - The instances of a potential subclass participate in a relationship unique to that subclass. - DONE Block 3 - DONE DB transaction management - - DONE anomalies - :LOGBOOK: - CLOCK: [2023-06-14 Wed 16:41:52]--[2023-06-14 Wed 16:49:14] => 00:07:22 - :END: - - DONE Deadlock and how it can be resolved. #flashcard - id:: 64841da4-d8ce-46f5-bbe6-4dee620cde75 - - 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. - - Example: - - Cascading rollback #flashcard - id:: 64897f0b-dda6-4cc3-a9c3-cf630bcb0658 - - Cascading Rollback: a transaction (T1) causes a - failure and a rollback must be performed. Other - transactions dependent on T1's actions must also - be rollbacked, thus causing a cascading effect. - - One transaction's failure causes many to fail. + - DONE Deadlock and how it can be resolved. #flashcard + id:: 64841da4-d8ce-46f5-bbe6-4dee620cde75 + - 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. + - Example: + - Cascading rollback #flashcard + id:: 64897f0b-dda6-4cc3-a9c3-cf630bcb0658 + - Cascading Rollback: a transaction (T1) causes a + failure and a rollback must be performed. Other + transactions dependent on T1's actions must also + be rollbacked, thus causing a cascading effect. + - One transaction's failure causes many to fail. - DONE ACID (Atomicity, Consistency, Isolation, Durability): A set of properties that guarantee the reliability and integrity of database transactions. #flashcard id:: 64841da4-0055-4d34-9f61-1402ff068ec7 collapsed:: true @@ -1102,6 +1098,7 @@ id:: 64842000-c15a-4b8f-95c3-d6c6e49e4af0 - Fourth Normal Form (4NF): 4NF is a further refinement of BCNF that ensures that _a table does not contain any multi-valued dependencies._ - Fifth Normal Form (5NF): 5NF is the highest level of normalization and involves decomposing a table into smaller tables to _remove data redundancy and improve data integrity._ + - Anomaly - LATER Block 4 - DONE Distributed DBMS - DONE client server arch #flashcard