CIS2750 Week 10 Questions and Correct Answers/ Latest Update / Already Graded

problems with concurrent access Ans: - tables in databases are being used with multiple users at the same time - multi-step queries often require a select/calculate/update sequence on one or more rows of tables which can cause issues when 2 people try to update the same data - solutions for the concurrent access problems Ans: - locking - transactions table locking Ans: - when one client gets control of the table, finishes their updates, then control is relinquished to other users row locking Ans: - better than table locking as only the rows that are being used by the first user are locked, the rest are available for use Page | 2 All rights reserved © 2025/ 2026 | transactions Ans: a series of database operations that form a logical package, needing to be performed together without interference, so this whole sequence has to be perfomed before anything about the data set can change - to be reliable they need to satisfy the ACID properties ACID stands for Ans: Atomicity, Consistency, Isolation, Durability ACID gives us Ans: the desired reliability we seek in database transactions To properly support transactions, a DBMS should be Ans: ACID compliant Atomocity Ans: When a transaction is an all-or-one proposition Page | 3 All rights reserved © 2025/ 2026 | - either all the statements change the database or none of them do, any action that's done to the database is a combination of the statements Consistency Ans: guarantees to keep data in other parts of the database consistent with a transaction by either tidying up implications of a transactions elsewhere or giving us an error message when we try to do something th