Which SQL command is used to delete records from a table?
- DELETE
- DROP
- REMOVE
- TRUNCATE
The DELETE command is used to remove rows from a table based on a specified condition. It is commonly used to delete specific records or all records from a table depending on the condition.
The Recovery Point Objective (RPO) defines the maximum acceptable ________ of data loss during a disaster.
- Amount
- Duration
- Frequency
- Severity
The Recovery Point Objective (RPO) specifies the maximum acceptable frequency of data loss during a disaster. It helps in determining the interval between data backups or replication to ensure minimal data loss in case of a disaster.
Which data type is appropriate for storing date and time values in DB2?
- DATE
- DECIMAL
- FLOAT
- VARCHAR
The DATE data type in DB2 is specifically designed to store date values. It ensures proper storage and manipulation of dates without the need for additional formatting or conversions.
When should the Reorg utility be used in DB2?
- After extensive data deletion
- To create a new table space
- To optimize SQL queries
- To update database schema
The Reorg utility in DB2 is typically used after extensive data deletion, which leaves the table fragmented. Reorganization rearranges the data physically, eliminating fragmentation and reclaiming space, thus improving performance. It's not used to create new table spaces, update schema, or optimize queries.
Which of the following is a potential drawback of denormalization?
- Enhanced query performance
- Improved data integrity
- Increased risk of data inconsistency
- Reduced storage space
One potential drawback of denormalization is the increased risk of data inconsistency. Denormalizing tables may lead to duplicated data across the database, making it more challenging to maintain data consistency. Changes to data in one location may not be reflected in all duplicated instances, resulting in inconsistencies. Thus, careful consideration is needed while denormalizing to balance performance benefits with the risk of data inconsistency.
Scenario: A database administrator is considering denormalizing certain tables to improve query performance. However, they are concerned about potential data redundancy. How would you advise them on mitigating this risk?
- Use triggers
- Employ data partitioning
- Establish referential integrity constraints
- Implement proper indexing
Option 4: Implement proper indexing - When denormalizing tables, it's crucial to implement proper indexing to mitigate the risk of data redundancy. Indexes help optimize query performance by facilitating efficient data retrieval. By creating indexes on the denormalized tables, the database administrator can ensure that queries execute swiftly while minimizing the impact of redundant data. Therefore, advising the administrator to implement proper indexing is the most appropriate way to mitigate the risk of data redundancy when denormalizing tables.
Which component of a stored procedure allows it to accept input parameters?
- Cursor
- Declaration Section
- Parameter List
- Result Sets
The Parameter List component of a stored procedure allows it to accept input parameters. Input parameters provide a way to pass values into the stored procedure at runtime, enabling dynamic behavior and enhancing the flexibility of the procedure. Developers can define parameters within the stored procedure declaration, specifying their data types and characteristics.
What is the purpose of the Data Manager component in DB2's architecture?
- Handles data storage and retrieval
- Manages database buffers
- Manages database connections
- Processes SQL queries
The Data Manager in DB2's architecture is responsible for handling data storage and retrieval operations. It manages the physical storage of data on disk and retrieves requested data efficiently using various optimization techniques such as buffering and caching. This component ensures that data is stored securely and can be accessed quickly by applications.
What is the difference between CHAR and VARCHAR data types in DB2?
- Date and time data types
- Fixed-length strings
- Numeric data types
- Variable-length strings
In DB2, the CHAR data type stores fixed-length character strings, whereas VARCHAR stores variable-length character strings. CHAR requires padding with spaces, while VARCHAR does not.
Performance tuning capabilities in IBM Data Studio contribute to optimizing ________.
- Database schema
- Indexes
- Network traffic
- SQL statements
IBM Data Studio's performance tuning capabilities include optimizing indexes, which play a crucial role in enhancing database performance by efficiently accessing and retrieving data.