In SQL, a _______ statement is used to define the structure of a database.
- CREATE
- INSERT
- SELECT
- UPDATE
In SQL, the CREATE statement is used to define the structure of a database. It allows you to create tables, define relationships, and set constraints, shaping the overall architecture of the database.
What are some best practices for managing conflicts in version control for data modeling?
- Ignoring conflicts to maintain stability
- Regularly merging changes from different branches
- Restricting access to version control
- Utilizing a centralized version control system
Best practices for managing conflicts include regularly merging changes from different branches. This ensures that updates from various contributors are incorporated, reducing conflicts and maintaining a consistent data model across the team.
Scenario: A company wants to ensure that every order placed in their system has a corresponding customer. Which type of constraint would you apply to the order table to enforce this rule?
- Check Constraint
- Foreign Key Constraint
- Primary Key Constraint
- Unique Constraint
To ensure that every order has a corresponding customer, you would apply a Foreign Key Constraint to the order table. This constraint establishes a link between the order table and the customer table, preventing orders without a matching customer.
In a one-to-many relationship, which entity holds the foreign key?
- Both entities
- It depends on the database design
- Many entities
- One entity randomly chosen
In a one-to-many relationship, the entity on the "many" side holds the foreign key. This key establishes the link between the two tables, allowing the "many" side to reference the primary key of the "one" side.
Which type of NoSQL database is best suited for hierarchical data with dynamic schemas?
- Column-family database
- Document-oriented database
- Graph database
- Key-value store database
A document-oriented database is best suited for hierarchical data with dynamic schemas. It allows storing complex, nested data structures in a document format (e.g., JSON or XML), making it flexible for evolving data requirements.
Which NoSQL database type is most suitable for graph-based data modeling?
- Column-family Store
- Document Store
- Graph Database
- Key-Value Store
Graph databases are the most suitable NoSQL type for graph-based data modeling. They are designed to represent and store data as nodes, edges, and properties, making them highly efficient for managing complex relationships in interconnected data sets.
Version control in data modeling helps to ensure _______ of data models.
- Collaboration
- Consistency
- Flexibility
- Security
Version control ensures consistency of data models by tracking changes and allowing users to revert to previous states if needed. It prevents conflicts and discrepancies, providing a stable and reliable model over time.
In a relational database, what does a one-to-many relationship imply?
- Each record in the "many" table can be related to multiple records in the "one" table
- Each record in the "many" table can be related to only one record in the "one" table
- Each record in the "one" table can be related to multiple records in the "many" table
- Each record in the "one" table can be related to only one record in the "many" table
A one-to-many relationship in a relational database implies that each record in the "one" table can be related to multiple records in the "many" table. This type of relationship is fundamental in database design and is often represented using foreign keys.
_______ is the process of reorganizing data into separate sections to improve manageability and performance.
- Denormalization
- Normalization
- Partitioning
- Sharding
Partitioning is the process of reorganizing data into separate sections or partitions. This technique helps in managing large datasets more efficiently, improving query performance, and optimizing data storage and retrieval processes.
What are the key differences between a fact table and a transactional table in a relational database?
- Fact tables are used for online transaction processing (OLTP), while transactional tables are used for online analytical processing (OLAP)
- Fact tables contain aggregated data, while transactional tables store detailed, raw data
- Fact tables have a primary key, while transactional tables have foreign keys
- Fact tables store current data, while transactional tables store historical data
Fact tables in a relational database store aggregated data, often derived from transactional tables. Transactional tables, on the other hand, store detailed, raw data. Recognizing these differences is essential for efficient database design and querying in both OLAP and OLTP environments.