How does polymorphism relate to superclasses and subclasses?
- It allows different subclasses to have different implementations of the same method
- It enables a superclass to inherit properties from its subclasses
- It ensures that each subclass has the same set of attributes
- It restricts the use of subclasses in a polymorphic relationship
Polymorphism, in the context of superclasses and subclasses, allows different subclasses to have different implementations of the same method. This flexibility in behavior enhances the adaptability of the database model.
In a graph database, nodes represent _______ and edges represent _______.
- Data, Connectivity
- Entities, Relationships
- Records, Attributes
- Tables, Columns
In a graph database, nodes represent entities, and edges represent relationships. Nodes store information about individual entities, while edges define the connections or relationships between these entities. This graph structure is particularly useful for representing and traversing complex relationships in data.
A financial institution needs to store transaction records of millions of customers securely while ensuring quick access to historical data. How could partitioning be utilized in the relational schema design to meet these requirements?
- Composite partitioning based on customer ID and transaction date
- Hash partitioning based on customer ID
- List partitioning based on transaction type
- Range partitioning based on transaction date
In this case, range partitioning based on transaction date could be employed to efficiently store and retrieve historical transaction data. Range partitioning organizes data based on specified ranges, making it easier to manage large datasets and optimize query performance for time-based queries.
In relational schema design, what is the purpose of keys and constraints?
- Enhance data security
- Ensure data consistency
- Facilitate data migration
- Improve query performance
Keys and constraints in relational schema design serve the purpose of ensuring data consistency. Keys (like primary and foreign keys) maintain unique relationships between tables, and constraints define rules that the data must adhere to, contributing to a reliable and coherent database.
What distinguishes column-family stores from traditional relational databases?
- Ability to scale horizontally
- Optimized for transactional processing
- Support for SQL queries
- Use of a fixed schema
One of the key distinctions is that column-family stores are designed to scale horizontally, allowing them to handle large volumes of data by distributing it across multiple nodes. This is in contrast to traditional relational databases, which often scale vertically by adding more resources to a single server.
Scenario: A multinational corporation operates data centers across different regions. How would you design a partitioning strategy to ensure efficient data distribution and access in a globally distributed environment?
- Geographical partitioning
- No partitioning needed in a global setup
- Partitioning based on employee roles
- Replication of entire databases
Geographical partitioning is the appropriate approach in a globally distributed environment. It involves dividing data based on the location of the data centers, facilitating faster access to data for users in specific regions. This helps in optimizing data distribution and retrieval across the multinational corporation's network.
Scenario: A car rental company offers different types of vehicles such as cars, trucks, and vans. How would you implement a superclass-subclass relationship to represent this scenario in a database?
- Create separate databases for cars, trucks, and vans
- Create separate tables for each vehicle type
- Implement a superclass-subclass relationship with a vehicle superclass and car/truck/van subclasses
- Use a single table for all vehicles with a column specifying the vehicle type
In this scenario, implementing a superclass-subclass relationship with a vehicle superclass and car/truck/van subclasses is the appropriate approach. It allows common attributes to be stored in the superclass while specific attributes for each vehicle type can be stored in the respective subclasses. This ensures data consistency and facilitates efficient querying.
The choice of clustering key impacts the _______ of data access operations.
- Complexity
- Cost
- Security
- Speed
The choice of clustering key impacts the speed of data access operations. The clustering key determines the physical organization of data, affecting how quickly and efficiently data can be retrieved during queries. It is crucial to choose an appropriate clustering key for optimal performance.
What are some advantages of using document-based modeling in a distributed system architecture?
- Easy horizontal scaling, as documents can be distributed across multiple nodes
- Efficient vertical scaling, with a focus on centralized storage
- Faster data retrieval through complex joins
- Limited scalability due to rigid schema requirements
Document-based modeling in a distributed system architecture offers advantages like easy horizontal scaling. Documents can be distributed across multiple nodes, allowing for seamless scalability as the system grows. This flexibility is particularly beneficial for distributed and cloud-based applications.
In an ERD, what is the purpose of an associative entity?
- To eliminate redundancy in data
- To enforce referential integrity
- To establish a many-to-many relationship between two entities
- To simplify the database structure
The purpose of an associative entity in an ERD is to establish a many-to-many relationship between two entities. It acts as a bridge table, resolving complex relationships by breaking them into simpler one-to-many relationships, which enhances the overall database design.