WorksheetsADBMS_Quiz_3_C
Total questions: 10
Worksheet time: 5mins
An equivalence rule in query optimization allows:
Identifying primary keys
Converting expressions into different languages
Shortening queries
Rewriting expressions without changing output
Query evaluation plans differ in:
Output format
Cost and performance
Query length
Syntax
In the query SELECT balance FROM account WHERE balance < 2500;, which relational algebra operation represents filtering?
σ (sigma)
× (cross product)
∪ (union)
Π (pi)
What is the main purpose of query parsing?
Generate output
Optimize query
Evaluate results
Check syntax and translate SQL to internal format
A homogeneous distributed database system uses:
Only cloud storage
Unique data models
Same DBMS and OS at all sites
Multiple schemas
In distributed systems, performance improves due to:
Local processing at sites
High network latency
Fewer users
More complex queries
A DBMS that can handle multiple data models and systems is:
Centralized
Heterogeneous distributed
Homogeneous
File-based
Which database type would support a military control system needing continuous access and high reliability?
NoSQL Document Store
Distributed DBMS
Centralized SQL Server
Local flat-file DB
What type of fragmentation is used when separating customer data by city?
Vertical
Horizontal
Indexed
Replicated
To reconstruct original data from vertical fragmentation, we use:
Selection
Union
Join
Cross-product
