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Data Journalism
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🪓data journalism review

10.3 Database design for journalistic projects

Citation:

Database design is crucial for journalistic projects. It's about organizing data efficiently, ensuring accuracy, and enabling easy retrieval. Good design considers the project's scope, data types, relationships, and future growth.

The structure includes entities, attributes, and relationships. Normalization reduces redundancy, while constraints maintain integrity. Choosing the right data types and optimizing for performance are key. These elements form the foundation for effective data management in journalism.

Database Design Considerations

Defining the Purpose and Scope

  • Clearly define the purpose and scope of the database based on the specific needs and goals of the journalistic project
  • Identify the types of data to be stored in the database
    • Structured data (numbers, dates)
    • Unstructured data (text, images, audio, video)
  • Determine the relationships between different entities or objects in the database to establish how data is connected and organized

Planning for Performance and Growth

  • Estimate the expected volume and growth of data over time to ensure the database design can accommodate future scalability
  • Consider the required performance and response time of the database to optimize queries and ensure efficient data retrieval
  • Plan the maintenance and update processes for the database
    • Data backups
    • Data validation
    • Error handling

Addressing Security and Privacy

  • Address the security and privacy requirements for the data
    • Access controls
    • Data encryption
    • Compliance with relevant regulations (GDPR)

Database Schema Structure

Defining Entities and Attributes

  • A database schema is a blueprint that defines the structure, organization, and relationships of data in a database
  • Entities represent real-world objects or concepts that need to be stored and managed in the database (articles, authors, sources)
  • Attributes are the properties or characteristics of an entity (article title, author name, source URL)

Establishing Relationships

  • Relationships describe how entities are connected to each other
    • One-to-one relationships: one record in a table is related to only one record in another table
    • One-to-many relationships: one record in a table can be related to multiple records in another table
    • Many-to-many relationships: multiple records in one table can be related to multiple records in another table, often requiring an intermediary table
  • Primary keys uniquely identify each record in a table, serving as a unique identifier for the entity
  • Foreign keys establish relationships between tables by referencing the primary key of another table

Optimizing Query Performance

  • Indexes can be created on frequently accessed columns to improve query performance and speed up data retrieval

Database Normalization

Normal Forms

  • Database normalization is the process of organizing data in a database to minimize redundancy and dependency, resulting in a more efficient and maintainable database structure
  • The First Normal Form (1NF) ensures that each column in a table contains atomic values (indivisible) and there are no repeating groups of data
  • The Second Normal Form (2NF) requires that all non-key columns in a table are fully dependent on the entire primary key, eliminating partial dependencies
  • The Third Normal Form (3NF) eliminates transitive dependencies, ensuring that non-key columns are not dependent on other non-key columns
  • Higher normal forms (4NF, 5NF) address more complex dependencies and are less commonly used in practice

Balancing Normalization and Performance

  • Denormalization is the intentional introduction of redundancy to improve query performance
    • Should be used judiciously to balance data integrity and performance

Data Types and Constraints

Choosing Appropriate Data Types

  • Data types define the kind of data that can be stored in a column (integers, floating-point numbers, strings, dates, binary data)
  • Choosing the appropriate data type for each column helps optimize storage space and ensures data consistency

Enforcing Data Integrity with Constraints

  • Constraints are rules enforced on the data in a table to maintain data integrity and accuracy
  • Primary key constraints ensure that the values in a column or a combination of columns are unique and not null, serving as a unique identifier for each record
  • Foreign key constraints enforce referential integrity by ensuring that values in a column match the values in the primary key of another table
  • Unique constraints ensure that the values in a column or a combination of columns are unique, preventing duplicate entries
  • Not null constraints require that a column must have a value, preventing null or missing values
  • Check constraints validate data based on a specified condition or expression (ensuring a value falls within a specific range or meets a certain format)
  • Default constraints specify a default value for a column when no value is provided during insertion