Question 1: True or False Question Answer We need transactions management for system effectiveness. In an E/R diagram, the relations cannot have their own keys. In a database system, we use...

Extracted text: Question 1: True or False Question Answer We need transactions management for system effectiveness. In an E/R diagram, the relations cannot have their own keys. In a database system, we use write-ahead logging to achieve concurrency. We should avoid interleaving transactions. A schedule with Write-Write conflicts cannot be converted to a serial schedule. In strict 2PL, the program cannot access to the data when there is a lock on it. We prefer RAM than Disk since it is durable. The external merge sort algorithm can be complete with as little as two buffer pages.