Slide 1
... • Each entity in an entity type needs to be identified uniquely Sometimes artificial attributes are created to facilitate this identification » E.g. student#, employee# ...
... • Each entity in an entity type needs to be identified uniquely Sometimes artificial attributes are created to facilitate this identification » E.g. student#, employee# ...
slides
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
A Closer Look
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
Transactions
... – e.g. sum of balances of all accounts, minus sum of loan amounts must equal value of cash-in-hand A transaction must see a consistent database. During transaction execution the database may be temporarily inconsistent. When the transaction completes successfully the database must be ...
... – e.g. sum of balances of all accounts, minus sum of loan amounts must equal value of cash-in-hand A transaction must see a consistent database. During transaction execution the database may be temporarily inconsistent. When the transaction completes successfully the database must be ...
ch15
... transaction may not be serializable – it may find some records inserted by a transaction but not find others. Read committed — only committed records can be read, but ...
... transaction may not be serializable – it may find some records inserted by a transaction but not find others. Read committed — only committed records can be read, but ...
Chapter 2 Notes
... Result: Database state no longer corresponds to real-world state, integrity constraint violated. ...
... Result: Database state no longer corresponds to real-world state, integrity constraint violated. ...
ppt
... Result: Database state no longer corresponds to real-world state, integrity constraint violated. ...
... Result: Database state no longer corresponds to real-world state, integrity constraint violated. ...
Overview of Transaction Processing Systems
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
A Closer Look
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
... • Execution of one transaction is not affected by the operations of another since they do not overlap in time ...
Concurrency and Transaction Management in an Object Oriented
... Strict 2PL—a transaction does not release any of its exclusive (write) locks until after it commits or aborts ...
... Strict 2PL—a transaction does not release any of its exclusive (write) locks until after it commits or aborts ...
50401A-ENU_Powerpnt_08
... • Grant the HR manager with the view and update rights to all the data. The management team has a requirement to generate performance metric for the sales staff. For this purpose, you are required to add a new function to the QuantamCorp HR VASE database that will import information from the CRM dat ...
... • Grant the HR manager with the view and update rights to all the data. The management team has a requirement to generate performance metric for the sales staff. For this purpose, you are required to add a new function to the QuantamCorp HR VASE database that will import information from the CRM dat ...
INTRODUCTION TO TRANSACTION PROCESSING
... Atomicity: A transaction is an atomic unit of processing; it is either performed in its entirety or not performed at all ...
... Atomicity: A transaction is an atomic unit of processing; it is either performed in its entirety or not performed at all ...
A Closer Look
... • The effect of concurrently executing a set of transactions must be the same as if they had executed serially (serializable) in some order. • Serializable has better performance than serial, but performance might still be inadequate. Database systems offer several isolation levels with different pe ...
... • The effect of concurrently executing a set of transactions must be the same as if they had executed serially (serializable) in some order. • Serializable has better performance than serial, but performance might still be inadequate. Database systems offer several isolation levels with different pe ...
Transaction Management (cont.)
... transactions following a failure. • May need to undo effects of transactions that had not committed at time of failure. • Essential that log records are written before write to database. Write-ahead ...
... transactions following a failure. • May need to undo effects of transactions that had not committed at time of failure. • Essential that log records are written before write to database. Write-ahead ...
Transaction Management Overview
... Log records are chained together by transaction id, so it’s easy to undo a specific transaction. The log is often duplexed and archived on stable storage. All log related activities (and in fact, all concurrency control related activities such as lock/unlock, dealing with deadlocks etc.) are handled ...
... Log records are chained together by transaction id, so it’s easy to undo a specific transaction. The log is often duplexed and archived on stable storage. All log related activities (and in fact, all concurrency control related activities such as lock/unlock, dealing with deadlocks etc.) are handled ...
Lecture Notes - Duncan College
... For example, we can use transactions to guarantee that money is not created or destroyed during online transfers. ...
... For example, we can use transactions to guarantee that money is not created or destroyed during online transfers. ...
A Closer Look
... Result: Database state no longer corresponds to real-world state, integrity constraint violated. ...
... Result: Database state no longer corresponds to real-world state, integrity constraint violated. ...
Transactions Transactions Transaction Concept Example of Fund
... be serializable – it may find some records inserted by a transaction but not find others. reads of record may return different (but committed) values. ...
... be serializable – it may find some records inserted by a transaction but not find others. reads of record may return different (but committed) values. ...
CSC 443 – Database Management Systems Databases
... – But DBMS is not infallible: programmers should have an idea of strategies used by DBMS so they can design better tables, indices, statements, in such a way that DBMS can ...
... – But DBMS is not infallible: programmers should have an idea of strategies used by DBMS so they can design better tables, indices, statements, in such a way that DBMS can ...
Transaction Management Overview
... (Non-strict) 2PL also allows only serializable schedules, but involves more complex abort processing ...
... (Non-strict) 2PL also allows only serializable schedules, but involves more complex abort processing ...
Failures in DBMS
... sequence of transactions (reads and writes). To understand database recovery, we must first understand the concept of transaction integrity. ...
... sequence of transactions (reads and writes). To understand database recovery, we must first understand the concept of transaction integrity. ...
Lecture 5
... An impasse that may result when two (or more) transactions are each waiting for locks held by the other to be released. ...
... An impasse that may result when two (or more) transactions are each waiting for locks held by the other to be released. ...
CSc-340 10a
... Extension to test for view serializability has cost exponential in the size of the precedence graph. ...
... Extension to test for view serializability has cost exponential in the size of the precedence graph. ...