Scenario: A company is designing an ERD for its HR system. They identify a scenario where an employee may have multiple dependents, but a dependent can only belong to one employee. What type of relationship does this represent in the ERD?
- Many-to-Many
- None of the above
- One-to-Many
- One-to-One
This scenario illustrates a One-to-Many relationship in the ERD. It implies that one employee can have multiple dependents, but each dependent can only be associated with one employee.
Explain the concept of transitive dependency in the context of normalization.
- A field depends on another field which is not the primary key
- A field depends on the primary key through another non-prime attribute
- A non-prime attribute depends on another non-prime attribute
- A primary key depends on a non-prime attribute
Transitive dependency occurs in a relation when a non-prime attribute depends on another non-prime attribute, which, in turn, depends on the primary key. This dependency chain indicates that the non-prime attribute is indirectly dependent on the primary key through another non-prime attribute, violating the rules of normalization.
What are the key considerations for selecting an encryption algorithm in DB2?
- Compression ratio, backup speed, transaction throughput
- Database schema complexity, indexing efficiency, storage overhead
- Network latency, query optimization, user authentication
- Strength of encryption, performance impact, compatibility with regulatory requirements
When selecting an encryption algorithm in DB2, key considerations include the strength of encryption, performance impact, and compatibility with regulatory requirements. These factors ensure data security and compliance.
The VARIANCE() function in DB2 returns the ________ of the values in a column.
- Variance
- Standard Deviation
- Mean
- Median
The correct option is 1. The VARIANCE() function in DB2 calculates the variance of the values in a column, which represents how much the values in the column deviate from the mean value of the column.
In an ERD, a double-lined rectangle represents a(n) ________ entity.
- Dependent
- Derived
- Strong
- Weak
In an ERD, a double-lined rectangle represents a strong entity. A strong entity is one that exists independently of other entities and has its own unique identifier. It is not dependent on any other entity for its existence.
JDBC enables Java applications to communicate with DB2 databases through ________.
- API calls
- Connection pooling
- Object-relational mapping
- SQL queries
JDBC (Java Database Connectivity) allows Java applications to communicate with DB2 databases through API calls. JDBC provides a set of interfaces and classes for executing SQL queries, managing connections, and processing results.
Which aggregation function in DB2 is used to find the highest value in a column?
- AVG()
- COUNT()
- MAX()
- MIN()
The MAX() function in DB2 is used to find the highest value in a column. It returns the maximum value of the specified column. This function is particularly useful when you need to retrieve the highest value from a set of data in your database. It is commonly used in various analytical queries to identify maximum values, such as finding the highest sales amount or the maximum temperature recorded.
What are some features of DB2 that enhance performance tuning?
- Automated Statistics Collection
- Index Advisor
- Materialized Views
- Query Optimization
DB2 provides various features to enhance performance tuning, such as query optimization, which involves choosing the most efficient execution plan for a given query. This can significantly improve query performance by minimizing resource usage and reducing response times.
What does DB2 offer in terms of scalability?
- Automatic scaling, Manual scaling, Elastic scaling
- Dynamic resizing of resources, No support for scaling
- Horizontal scalability, Vertical scalability, Limited scalability, No scalability
- Scalable storage, Scalable processing power, Scalable memory
DB2 provides both horizontal and vertical scalability. Horizontal scalability involves adding more machines or nodes to a system to handle increased load, while vertical scalability involves increasing the resources (such as CPU, memory, or disk) on a single machine to accommodate growth. This flexibility enables DB2 to handle varying workloads efficiently.
Scenario: A developer is designing an application that requires high concurrency in DB2.
- Increase the transaction isolation level to ensure stronger consistency.
- Minimize transaction duration by breaking down tasks into smaller units.
- Use a deadlock detection mechanism and implement retry logic.
- Utilize Serializable isolation level to prevent concurrency-related issues.
In a high-concurrency environment, minimizing transaction duration by breaking tasks into smaller units can reduce the likelihood of conflicts and deadlocks. By keeping transactions short-lived, the system can handle more concurrent requests, optimizing throughput. This approach helps in avoiding contention for resources and ensures efficient utilization of system resources.
Which command line tool is commonly used for basic database administration tasks in DB2?
- DB2 Command Line Processor (CLP)
- MySQL Command Line Client
- SQL Server Management Studio
- SQL*Plus
The DB2 Command Line Processor (CLP) is commonly used for basic database administration tasks in DB2. It provides a command-line interface for executing SQL statements, managing database objects, and performing administrative tasks. CLP offers flexibility and efficiency for administrators to interact with the DB2 database system directly from the command line.
How does referential integrity ensure data integrity in DB2?
- By compressing the data
- By creating indexes
- By encrypting the data
- By enforcing relationships between tables
Referential integrity in DB2 ensures data integrity by enforcing relationships between tables. This means that when a foreign key in one table references a primary key in another table, the integrity of the relationship is maintained. For example, if a record in the parent table is deleted or updated, the corresponding records in the child table are also updated or deleted to maintain consistency. This helps prevent orphan records and ensures that the data remains accurate and consistent throughout the database.