Indexing
What type of index has an entry for every search key value in a data file?
dense index
What is another internal representations of a query in query optimization in addition to query graph?
query trees
What component of DBMS is in charge of choosing a suitable execution strategy for processing a query?
query optimizer
What is a logical unit of database processing that includes one or more access operations?
transaction
What happens when two transactions try to access the same data, and at least one modifies it?
conflict
What is the average linear search cost in block accesses for a data file with 30,000 records and 3,000 blocks?
1,500 block accesses
What is the term for the basic unit that can be translated into algebraic operators and optimized in query processing?
query block
What are the key cost components in cost-based query optimization?
block access
What are the two primary operations used in transaction management?
read and write
What is the term for a situation where two transactions wait for each other to release a resource indefinitely?
deadlock
In a single-level primary index, what is the term for the key field value of the first record in a block?
block anchor
What is by scanning two files ordered by their join attributes and matching records with the same values?
sort merge
What is iterating over each record in the outer relation and, for each, scanning all records in the inner relation to find matching tuples?
nested loop join
What is undoing all changes made by a transaction?
rollback
What is a sequence of operations in concurrent transactions called?
schedule
In a B-tree, what happens when a node becomes full during insertion?
splits into two nodes
What is the average number of records per block?
blocking factor
Which search method has log2b for cost, where b is the number of blocks?
binary search
What is by executing entirely or not at all, ensuring no partial changes in the properties of transation?
atomicity
What is the operation that reapplies changes made by a committed transaction during recovery?
redo
In a B+-tree, which type of node include only index key entry?
leaf node
What are the three key operations to optimize during heuristic query tree transformation?
SELECT, PROJECT, and JOIN
What is a directive provided by developers to influence the optimizer’s decisions, such as join order, access paths, or parallel execution?
Hint
What is ensuring that the intermediate states of a transaction are not visible to other transactions?
isolation
What is the operation that reverses changes made by an uncommitted transaction?
undo