ADBMS_Quiz_3_C

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