How does DB2 handle NULL values for columns defined with NOT NULL constraint?
- It allows NULL values
- It depends on the version of DB2
- It rejects any attempt to insert NULL values
- It replaces NULL with a default value
When a column is defined with a NOT NULL constraint, DB2 rejects any attempt to insert NULL values into that column. This ensures data integrity by enforcing the rule that the column must have a value for every row.
In DB2, what does XML or JSON data represent?
- Structured data
- Unstructured data
- Semi-structured data
- Binary data
XML or JSON data in DB2 represents semi-structured data. Semi-structured data combines aspects of both structured and unstructured data, allowing for flexibility in data organization while still maintaining some level of schema or format. XML and JSON are commonly used formats for representing semi-structured data due to their flexibility and widespread adoption in modern application development.
Point-in-time recovery in DB2 allows for recovery of data to a specific ________.
- Timestamp
- Table
- Transaction
- Checkpoint
The correct option is Option 1: Timestamp. Point-in-time recovery in DB2 enables the recovery of data to a specific timestamp, allowing users to restore the database to a particular moment in time, ensuring data consistency and integrity.
What are some considerations for I/O optimization in DB2 performance tuning?
- Increasing disk storage capacity
- Optimizing database schema for disk access
- Reducing network latency
- Utilizing Solid State Drives (SSDs)
I/O optimization in DB2 involves various strategies such as utilizing Solid State Drives (SSDs) for faster disk access, optimizing the database schema to minimize disk I/O operations, and implementing techniques like data partitioning or compression to reduce storage requirements and improve disk efficiency. By addressing these considerations, DB2 performance can be enhanced through improved I/O performance and reduced latency.
The CASCADE option in a FOREIGN KEY constraint in DB2 performs ________.
- Updates or deletes a row in the parent table, and automatically updates or deletes related rows
- Updates or deletes a row in the child table, and automatically updates or deletes related rows
- Deletes all rows in the parent table, and automatically updates or deletes related rows
- Deletes all rows in the child table, and automatically updates or deletes related rows
The CASCADE option in a FOREIGN KEY constraint specifies that when a referenced row in the parent table is updated or deleted, the corresponding rows in the child table are automatically updated or deleted accordingly. This ensures data consistency between related tables by propagating changes in the parent table to the child table. This option helps in maintaining referential integrity in the database.
Scenario: A company's DBA wants to restrict access to sensitive columns in a table for certain users. How can views be utilized to achieve this goal in DB2?
- Views can be created with joins to other tables, providing access control.
- Views can be created with row-level security policies, filtering sensitive data.
- Views can be created with specific columns included, hiding sensitive ones.
- Views can be created with triggers, enforcing access permissions.
Views can act as a security layer in DB2 by allowing DBAs to create views with only the necessary columns visible to certain users, thus restricting access to sensitive data. By creating views that include only non-sensitive columns or by excluding sensitive columns, DBAs can ensure that only authorized users have access to the required data without exposing sensitive information. This approach enhances data security and compliance with regulatory requirements.
Control Center is primarily used for ________ of DB2 databases.
- Administration
- Backup and Recovery
- Monitoring
- Performance Tuning
Control Center is primarily used for administration of DB2 databases. It provides a graphical user interface (GUI) that allows database administrators to perform various administrative tasks such as creating and managing database objects, monitoring database performance, and configuring security settings.
Scenario: A developer is tasked with identifying the highest and lowest sales amounts for a particular product. Which aggregation functions should they utilize in DB2, and how?
- MAX(), MIN()
- AVG(), SUM()
- COUNT(), AVG()
- MIN(), SUM()
The correct option is MAX(), MIN(). MAX() returns the highest value, and MIN() returns the lowest value. In this scenario, the developer needs to find the highest and lowest sales amounts, which can be achieved by using these functions. AVG() calculates the average, SUM() calculates the total sum, and COUNT() counts the number of rows.
XPath expressions in DB2 are used for ________ XML data.
- Inserting and updating
- Querying and navigating
- Sorting and filtering
- Validating and indexing
XPath expressions in DB2 are primarily used for querying and navigating XML data. XPath allows users to specify paths to elements or attributes within XML documents, facilitating data retrieval and manipulation.
How does Control Center differ from Command Line Tools in terms of functionality?
- Graphical user interface for database management
- Text-based interface for database management
- Both A and B
- None of the above
Control Center provides a graphical user interface (GUI) for managing DB2 databases, allowing users to visually interact with various database objects such as tables, schemas, and queries. On the other hand, Command Line Tools offer a text-based interface, enabling users to perform similar database management tasks through command-line commands. Both options A and B are correct because Control Center offers a GUI, whereas Command Line Tools offer a text-based interface.