LSP4YOU - Learner's Support Publications

DBMS BCA Unit-5 Transaction - Definition Transaction - Examples COMMIT and ROLLBACK Properties of a Transaction States of Transactions The Concurrent Transactions Transactions - Lost Updates Transactions - Unrepeatable Reads Transactions - Dirty Reads Transactions - Inconsistent Analysis Serialisable Schedule Serial and Interleaved Schedule Precedence Graph Algorithm Precedence Graph Construction Non Serializable Schedule Locking Protocol Locks and Types of Locks Binary Locks Multiple-Mode Locks Shared and Exclusive Locks Two Phase Locking (2PL) Types of Two Phase Locking Database Security Goals Types of Database Security Threats to Databases Database Security & Authorization Subsystem Discretionary Security Mechanisms Mandatory Security Mechanisms Control Measures Access Control Inference Control Flow Control Data Encryption Database Security and the DBA DBA - Privileged Commands DBA Role Access Control, User Accounts and Database Audits System Log Database Audit Audit Trail Sensitive Data and Types of Disclosures Sensitive Data - Classification Factors Factors - Data is Safe Discretionary Access Control in a Database Account Level Privileges Relation Level Privileges Access Matrix Model Privileges on Relations

Transactions - Dirty Reads

Problems of Concurrent Transactions: Dirty Reads

T10 reads a value that has been updated by T9. This update has not been committed and T9 aborts. T10 has read a value that would never exist in the database.