In NoSQL databases, which consistency model sacrifices consistency in favor of availability and partition tolerance?
- Causal Consistency
- Eventual Consistency
- Sequential Consistency
- Strong Consistency
Eventual Consistency in NoSQL databases sacrifices immediate consistency in favor of high availability and partition tolerance. It allows replicas of data to become consistent over time, ensuring that all replicas will eventually converge to the same value. This trade-off is suitable for systems where availability is crucial, and temporary inconsistencies can be tolerated.
Scenario: A hospital manages doctors, patients, and appointments. Each patient can have multiple appointments, each doctor can have multiple appointments, and each appointment is associated with one patient and one doctor. How would you represent this scenario in an ERD?
- Many-to-Many
- Many-to-One
- One-to-Many
- One-to-One
For this scenario, a One-to-One relationship is appropriate. Each appointment is associated with one patient and one doctor. It ensures that each appointment is uniquely linked to a specific patient and doctor, avoiding data redundancy.
In Forward Engineering, the process starts with a _______ data model and progresses towards a detailed physical model.
- Abstract
- Conceptual
- Concrete
- Logical
In Forward Engineering, the process begins with a Logical Data Model. This model represents the abstract structure of the data without concerning itself with the physical implementation. It serves as a bridge between the high-level conceptual model and the detailed physical model.
Which factor is typically NOT considered when deciding how to partition data?
- Data compression ratio
- Data distribution across servers
- Query performance requirements
- Security requirements
The data compression ratio is typically not considered when deciding how to partition data. Partitioning decisions are primarily based on factors such as data distribution, query performance, and security requirements, but compression considerations are addressed separately.
What is the primary focus of Dimensional Modeling?
- Data Integrity
- Normalization
- Performance for retrieval and analysis
- Transaction processing
The primary focus of Dimensional Modeling is optimizing performance for retrieval and analysis. Unlike normalization, which aims for data integrity through minimizing redundancy, Dimensional Modeling prioritizes efficient querying and reporting for analytical purposes. This involves designing structures that align with how users typically access and analyze data in a data warehouse.
Scenario: A database has a table with attributes {EmployeeID, ProjectID, HoursWorked}. Is this table in the third normal form (3NF)?
- Cannot be determined
- No
- Not applicable
- Yes
Yes
What are some challenges associated with storage optimization in cloud-based databases?
- Inability to scale horizontally
- Lack of data encryption options
- Limited control over underlying infrastructure
- Reduced data accessibility
Challenges in storage optimization for cloud-based databases include limited control over the underlying infrastructure. Cloud providers manage the hardware, making it essential for organizations to adapt to the cloud environment and optimize storage within the constraints of the chosen cloud platform.
Explain the concept of run-length encoding (RLE) in compression algorithms.
- Assigning unique codes to each character in the data
- Breaking down the data into smaller chunks for parallel processing
- Encoding consecutive repeated characters with a single data value and count
- Randomly shuffling the data to reduce predictability
Run-Length Encoding (RLE) is a compression technique that involves encoding consecutive repeated characters with a single data value and count. This is particularly effective for data with long sequences of identical elements, as it condenses repetitive patterns, resulting in a more compact representation of the information.
Data Marts are often built to serve the needs of a particular _______ or _______.
- Business Unit, Department
- Database, Table
- Time Period, Frequency
- User, Role
Data Marts are often built to serve the needs of a particular business unit or department. They are subsets of a larger Data Warehouse, focusing on specific business requirements and making it easier for a particular group to access and analyze relevant data.
Scenario: A financial institution manages a vast amount of transaction data in its database. Queries often involve retrieving transactions within specific date ranges or for particular account holders. How would you utilize indexing to enhance query performance in this scenario?
- Avoid indexing to prioritize storage space
- Create a clustered index on the date column and a non-clustered index on the account holder column
- Implement a non-clustered index on the date column
- Use a covering index on all transaction-related columns
For this scenario, creating a clustered index on the date column and a non-clustered index on the account holder column would enhance query performance. Clustered indexes dictate the physical order of data, and non-clustered indexes provide quick access to specific columns.
Scenario: A multinational corporation requires a database to manage its various departments, employees, and projects. How would you approach the conceptual schema design to accommodate diverse business needs and future scalability?
- Agile development, rapid prototyping, blockchain integration, and cloud-based storage
- Denormalization, hierarchical organization, strict access control, and centralized storage
- Normalization, modularization, role-based access control, and data partitioning
- Vertical partitioning, redundancy elimination, distributed databases, and flat file storage
In designing the conceptual schema for a multinational corporation, considerations should include normalization, modularization, role-based access control, and data partitioning to accommodate diverse business needs and ensure future scalability.
The _______ is used to represent the relationship between a subclass and its superclass in an ERD.
- Arrow
- Circle
- Line
- Triangle
The Line is used to represent the relationship between a subclass and its superclass in an ERD. It signifies the connection and inheritance of attributes from the superclass to the subclass.