How does DB2 handle data integrity issues caused by concurrent transactions?
- DB2 automatically aborts one of the conflicting transactions to resolve data integrity issues.
- DB2 creates duplicate copies of conflicting data to prevent data integrity violations.
- DB2 ignores data integrity issues caused by concurrent transactions and allows inconsistent results.
- DB2 resolves data integrity issues by using locks to control access to shared resources during concurrent transactions.
DB2 employs various concurrency control mechanisms, such as locking and isolation levels, to manage data integrity issues arising from concurrent transactions. By using locks, DB2 ensures that only one transaction can access a specific resource at a time, preventing conflicting updates and maintaining data consistency. Additionally, DB2 supports different isolation levels, allowing users to control the visibility of changes made by concurrent transactions to address consistency requirements.
How does DB2 ensure data integrity within databases?
- ACID properties, BASE properties, CAP theorem, No data integrity mechanisms
- Data redundancy, Data inconsistency, Data fragmentation
- Referential integrity, Constraints, Data validation rules
- Transactions, No support for transactions, Data replication
DB2 ensures data integrity through various mechanisms such as referential integrity, constraints, and data validation rules. Referential integrity constraints enforce relationships between tables to maintain data consistency, while constraints and validation rules define permissible data values and ensure data accuracy. By adhering to these principles, DB2 maintains the integrity and reliability of the stored data.
In DB2, a stored procedure can be used to encapsulate ________ logic.
- Application
- Business
- Data
- Presentation
Stored procedures in DB2 are commonly used to encapsulate business logic. Business logic refers to the rules and processes that govern the manipulation and management of data within an application. This can include calculations, validations, and other operations.
What does the INSERT INTO statement do in SQL?
- Adds new records
- Deletes records
- Sorts records
- Updates existing records
The INSERT INTO statement adds new records (rows) to a table in a database. It is used to insert a new row of data into a specified table with specified values for each column.
IBM Data Studio provides a user-friendly interface for ________ and managing DB2 databases.
- Designing
- Developing
- Monitoring
- Querying
IBM Data Studio is designed to assist developers in developing applications for DB2 databases. It provides tools and features for writing and debugging SQL queries, designing and modifying database schemas, monitoring database performance, and optimizing queries. Hence, it enhances developers' productivity by providing a comprehensive environment for all stages of application development, from design to deployment.
What is the primary purpose of the installation process in DB2?
- Configuring database settings
- Creating database objects
- Installing the necessary files
- Setting up user permissions
The primary purpose of the installation process in DB2 is to install the necessary files onto the system. This includes executable files, libraries, and other resources required for DB2 to operate correctly.
What role does XPath play in querying XML data in DB2?
- XPath is used for creating indexes on XML data.
- XPath is used for querying relational tables in DB2.
- XPath is used for schema validation of XML data.
- XPath is used to navigate through elements and attributes.
XPath plays a crucial role in querying XML data in DB2 by providing a syntax for navigating through the hierarchical structure of XML documents. It allows users to pinpoint specific elements or attributes within an XML document for retrieval or manipulation.
Data compression in DB2 reduces the size of data by eliminating ________.
- Duplicate records
- Redundant information
- Unused space
- Unwanted data
Data compression in DB2 works by identifying and removing redundant information within the dataset. This can include eliminating duplicate records, reducing unused space, or removing any unnecessary data that might be present, ultimately leading to a reduction in the overall size of the data stored in the database.
What are the advantages of using a scrollable cursor in DB2?
- Allows for executing complex SQL queries
- Allows for fetching rows in both forward and backward directions
- Improves database security
- Provides a way to create temporary tables
Scrollable cursors in DB2 offer the advantage of fetching rows in both forward and backward directions. This is useful when navigating through large result sets, as it enables efficient data retrieval and manipulation. By using a scrollable cursor, developers can easily move back and forth within the result set without re-executing the query. This feature enhances application performance and user experience, especially in scenarios where users need to browse through extensive data sets.
Scenario: During peak hours, several users report slow query performance. How can the DB2 administrator identify the cause and resolve the issue promptly?
- Disable unnecessary applications to reduce system load
- Enable monitoring tools to capture SQL performance metrics
- Increase hardware resources such as CPU and memory
- Restart the DB2 instance to clear any temporary bottlenecks
Enabling monitoring tools to capture SQL performance metrics allows the DB2 administrator to identify poorly performing queries during peak hours. These tools can provide insights into various metrics such as execution time, I/O operations, and locking behavior, enabling the administrator to pinpoint the cause of slow query performance. Increasing hardware resources or restarting the DB2 instance may provide temporary relief but may not address the root cause of the issue. Disabling unnecessary applications can reduce system load but may not directly address SQL performance concerns.