1. Question: What is Db2?
- Answer: IBM Db2
is a family of data management products, including database servers, developed
by IBM. It is a relational database management system (RDBMS) known for its
performance, scalability, and reliability.
2. Question: Explain the difference between Db2 LUW (Linux,
Unix, Windows) and Db2 z/OS (Mainframe).
- Answer: Db2 LUW
is designed for distributed systems like Linux, Unix, and Windows, while Db2
z/OS is designed for IBM mainframe systems. The architecture, features, and
management of these versions differ to meet the requirements of their
respective environments.
3. Question: What is Db2's isolation levels, and how do they
impact transactions?
- Answer: Db2
supports isolation levels like Read Uncommitted, Read Committed, Repeatable
Read, and Serializable. These levels determine the visibility of data changes
made by other transactions during the execution of a transaction, impacting
consistency and concurrency.
4. Question: Explain the purpose of Db2 tablespaces.
- Answer: Db2
tablespaces are storage structures that group related database objects
together. Tables and indexes are stored in tablespaces, allowing for efficient
management of storage.
5. Question: What is a Db2 package, and how is it related to
stored procedures?
- Answer: In Db2, a
package is a compiled form of a SQL statement or a set of SQL statements.
Stored procedures are often bound into packages, which are then executed by the
Db2 engine.
6. Question: How does Db2 handle transactions, and what is a
Db2 commit statement?
- Answer: Db2 uses
a two-phase commit protocol for transactions. The COMMIT statement in Db2 is
used to save the changes made during a transaction permanently.
7. Question: Explain the purpose of Db2 indexes and their
types.
- Answer: Db2
indexes are structures that provide a fast access path to data in a table.
Types of Db2 indexes include unique, non-unique, clustered, and non-clustered
indexes.
8. Question: What is the Db2 Catalog and Directory?
- Answer: The Db2
Catalog contains metadata about the database, such as tables, indexes, and
privileges. The Db2 Directory contains information about the physical layout of
the database, including tablespaces and storage groups.
9. Question: How can you optimize a query in Db2?
- Answer: Query
optimization in Db2 involves creating appropriate indexes, using RUNSTATS to
update statistics, and using the Db2 Visual Explain tool to analyze and
optimize query execution plans.
10. Question: Explain the purpose of Db2's Explain
Statement.
- Answer: The
EXPLAIN statement in Db2 is used to analyze the access plan for a SQL
statement. It provides information about how Db2 will execute the statement,
helping in query performance tuning.
11. Question: What are Db2 triggers, and how are they used?
- Answer: Db2
triggers are sets of instructions that are automatically executed (or
"triggered") in response to specific events, such as INSERT, UPDATE,
or DELETE operations on a table. They are used for enforcing business rules or
maintaining data integrity.
12. Question: What is Db2's Automatic Storage feature?
- Answer:
Automatic Storage is a feature in Db2 that simplifies storage management by
automatically creating and managing storage objects, such as containers and
tablespaces. It reduces the manual effort required for storage administration.
13. Question: Explain the concept of Db2 isolation levels.
- Answer: Db2
isolation levels determine the visibility of changes made by one transaction to
other concurrent transactions. Common isolation levels include Uncommitted
Read, Cursor Stability, Repeatable Read, and Serializable.
14. Question: How does Db2 handle deadlock situations?
- Answer: Db2
resolves deadlocks by selecting a victim transaction to be rolled back. It uses
the lock timeout mechanism and a deadlock detection algorithm to identify and
resolve deadlocks.
15. Question: What is Db2's High Availability Disaster
Recovery (HADR) feature?
- Answer: HADR in
Db2 is a feature that provides high availability and disaster recovery
capabilities. It involves creating a standby database that can take over in
case the primary database fails, ensuring business continuity.
16. Question: What is Db2's Multi-Versioning Concurrency
Control (MVCC)?
- Answer: MVCC is
a mechanism in Db2 that allows multiple transactions to access a database
concurrently without locking. It ensures data consistency by providing each
transaction with a snapshot of the data at the start of the transaction.
17. Question: What is Db2 pureScale, and how does it enhance
scalability?
- Answer: Db2
pureScale is a feature that enables seamless database scaling by allowing
multiple Db2 servers to work together as a single, highly available system. It
enhances scalability by distributing the workload across multiple servers.
18. Question: Explain the purpose of the Db2 LOAD utility.
- Answer: The LOAD
utility in Db2 is used for efficiently loading large amounts of data into a
table. It is faster than using INSERT statements and is commonly used during
data migration or data warehousing tasks.
19. Question: What is Db2's Data Encryption feature?
- Answer: Db2
provides data encryption features to secure sensitive data. This includes
Transparent Data Encryption (TDE) for encrypting data at rest and Secure
Sockets Layer (SSL) for encrypting data in transit.
20. Question: How can you secure a Db2 database?
- Answer: Securing
a Db2 database involves implementing strong authentication, defining proper
user privileges, encrypting data, regularly applying security patches, and
monitoring database activities for suspicious behavior. Additionally, auditing
and compliance features can be utilized for security assurance.
