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.
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.
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.
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.
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.
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.
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.
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.
Scenario: A database designer is creating an ERD for a banking system. They encounter a scenario where a customer may have multiple accounts, but an account can only belong to one customer. 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 represents a One-to-Many relationship in the ERD. In a One-to-Many relationship, one entity instance can be associated with multiple instances of another entity, but each instance of the second entity can only be associated with one instance of the first entity. In this case, one customer can have multiple accounts, but each account can only belong to one customer.
Analyzing and optimizing the ________ can lead to better overall DB2 performance.
- Application code
- Buffer pools
- Database configuration
- Locking mechanisms
Analyzing and optimizing the database configuration, including parameters such as buffer pool sizes, can lead to better overall DB2 performance.