In a Snowflake Schema, how are dimension tables organized?
- Dimension tables are organized in a flat, denormalized structure
- Dimension tables are organized in a hierarchical, normalized structure
- Each dimension table is directly connected to the fact table
- Fact table is organized in a snowflake pattern
In a Snowflake Schema, dimension tables are organized in a hierarchical, normalized structure. Unlike a Star Schema, where dimension tables are directly connected to the fact table, Snowflake Schema allows for a more normalized representation of data, reducing redundancy.
Scenario: A multinational corporation requires a database design tool that can integrate with their existing software ecosystem, including enterprise resource planning (ERP) systems. They also need robust support for data security and compliance. Which database design tool would you suggest, and how does it meet the corporation's requirements?
- IBM Data Architect
- Microsoft SQL Server Management Studio (SSMS)
- Oracle SQL Developer
- SAP PowerDesigner
SAP PowerDesigner is recommended for its ability to integrate with enterprise software ecosystems, including ERP systems. It also provides robust support for data security and compliance, making it suitable for the stringent requirements of a multinational corporation.
Can a subclass have multiple superclasses in a Generalization and Specialization hierarchy? Explain.
- No, a subclass can only have one superclass
- No, multiple superclasses violate normalization principles
- Yes, but it leads to data redundancy
- Yes, through multiple inheritances
In a Generalization and Specialization hierarchy, a subclass can have multiple superclasses through multiple inheritances. However, this approach introduces complexities and potential issues like ambiguity and data redundancy.
In Dimensional Modeling, what is a slowly changing dimension (SCD)?
- A dimension that changes at a variable rate
- A dimension that changes over time and requires historical tracking
- A dimension that changes rapidly over time
- A dimension that rarely changes
A slowly changing dimension (SCD) in Dimensional Modeling refers to a dimension that changes over time and requires historical tracking. It involves maintaining historical data for changes in dimension attributes to analyze trends and patterns over different points in time.
Which symbol is used to represent a relationship between entities in an ERD?
- Circle
- Diamond
- Rectangle
- Triangle
In an ERD, a diamond-shaped symbol is used to represent a relationship between entities. This symbol indicates how entities are connected or related to each other in the database schema. The lines drawn between entities and the diamond symbolize the nature and cardinality of the relationship.
What are some common strategies for implementing partitioning in a distributed database system?
- Interval partitioning, Nested partitioning, Join partitioning, Broadcast partitioning
- Range partitioning, Hash partitioning, List partitioning, Round-robin partitioning
- Subpartitioning, Federation, Denormalization, Normalization
- Vertical partitioning, Distributed partitioning, Sharding, Replication
Common strategies for implementing partitioning in a distributed database system include Range partitioning (dividing data based on ranges), Hash partitioning (using a hash function), List partitioning (based on a specified list of values), and Round-robin partitioning (equal distribution without specific criteria). These strategies aid in efficient data management and retrieval in a distributed environment.
Type 6 Slowly Changing Dimensions (SCD) combines features of Type 1, Type 2, and _______.
- Type 3
- Type 4
- Type 5
- Type 7
Type 6 SCD combines features of Type 1 (overwrite), Type 2 (preserve history), and Type 4 (maintain history in a separate table). This type is versatile and suits scenarios where a comprehensive history, including changes in both dimensions and attributes, is necessary.
Scenario: You are designing a social networking platform where users can follow other users and share posts. Which NoSQL database type would you choose and why?
- Column-family Store
- Document Store
- Graph Database
- Key-Value Store
For a social networking platform with complex relationships like followers and shared posts, a Graph Database would be suitable. Graph databases excel at handling relationships between entities, making it efficient to represent connections between users and their activities in this scenario.
Scenario: A financial institution requires immediate consistency across all its branches when updating account balances. Which consistency model would be most suitable for their NoSQL database?
- Causal Consistency
- Eventual Consistency
- Session Consistency
- Strong Consistency
Immediate consistency is crucial for a financial institution. Therefore, Strong Consistency is the most suitable model as it ensures that updates are instantly reflected across all branches without any delay or inconsistency.
Which stage of database development involves transforming a high-level conceptual model into a detailed physical model?
- Conceptual Design
- Logical Design
- Physical Design
- Requirements Analysis
The stage of database development that involves transforming a high-level conceptual model into a detailed physical model is the Physical Design stage. During this phase, decisions regarding storage structures, indexing, and other physical aspects of the database are made based on the logical design.