data and databases

• Data


  Raw, unorganized facts and figures that are collected, stored, and processed by computers
• Information

  Data that has been processed, organized, or structured in a meaningful way to make it useful
• Sources of data


  • Primary sources
  • Secondary sources
• Primary sources of data


  • Firsthand information
  • Original data
  • Reliable
• Secondary sources of data


  • Secondhand information
  • Processed data
  • Convenient
• Key differences between primary and secondary data
• Structured data


  Data that has a highly organized format, with each piece of data fitting into predefined categories and fields
• Structured data


  • Organized format
  • Easily searchable
• Unstructured data


  Data that lacks a specific structure or format, such as text, images, videos, or other media
• Unstructured data


  • Lack of organization
  • Varied formats
  • Difficult to analyze
• Relational database


  A type of database that uses a structure based on tables and the relationship between data elements

  
• Relational database


  • Tables
  • Records (Rows/Tuples)
  • Fields (Columns/Attributes)
  • Primary keys
  • Foreign keys
  • Composite keys
  • Data integrity
• Structured Query Language (SQL)

  A language used for querying and manipulating data in relational databases
• Relational databases provide a flexible and efficient way to store and manage structured data
• Popular examples of relational database management systems (RDBMS)

  • MySQL
  • PostgreSQL
  • Oracle
  • SQL Server
  • SQLite
• Reasons why databases are used to structure data


  • Data organization
  • Data integrity
• Data organization in databases


  • Efficiency
  • Quick retrieval
• Data integrity in databases


  • Data validation
  • Constraints
• Relational database management systems (RDBMS)

  • Widely used in various applications
  • Reliable
  • Scalable
  • Ability to handle complex relationships between data elements

  
• Why databases are used to structure data


  • Data Organization
  • Data Integrity
  • Data Security
  • Data Consistency
  • Data Retrieval and Analysis
  • Scalability and Performance
  • Data Backup and Recovery
  • Collaboration and Multi-User Support
  • Integration with Applications
• Data Organization


  • Efficiency: Databases organize data into tables, rows, and columns, making it structured and easy to manage
  • Quick Retrieval: Structured data allows for rapid search and retrieval of specific information, enhancing efficiency
• Data Integrity


  • Data Validation: Databases can enforce data integrity rules, ensuring that data entered conforms to predefined standards, preventing errors
  • Constraints: Databases allow the application of constraints (such as unique keys or foreign keys), maintaining the relationships between different pieces of data
• Data Security


  • Access Control: Databases provide robust user access control, allowing administrators to define who can view or modify specific data
  • Encryption: Sensitive data can be encrypted, adding a layer of security to prevent unauthorized access
• Data Consistency


  • Transaction Management: Databases support transactions, ensuring that multiple operations on data occur atomically, maintaining consistency
  • ACID Properties: Databases adhere to ACID properties (Atomicity, Consistency, Isolation, Durability), ensuring reliable transactions and consistent data state
• Data Retrieval and Analysis


  • Structured Query Language (SQL): Databases use SQL for querying, enabling complex searches, aggregations, and data analysis
  • Reporting: Structured data facilitates the generation of detailed reports and analytics, aiding decision-making processes
• Scalability and Performance


  • Indexing: Databases use indexes to optimize data retrieval, speeding up searches even with large datasets
  • Partitioning: Databases can be partitioned, distributing data across multiple storage devices for efficient scaling and performance
• Data Backup and Recovery


  • Backup: Databases allow for regular backups, ensuring data is not lost in case of hardware failures or other disasters
  • Point-in-Time Recovery: Databases often support point-in-time recovery, enabling restoration to a specific state before data loss occurred
• Collaboration and Multi-User Support


  • Concurrency Control: Databases manage simultaneous access by multiple users, ensuring that data modifications don't conflict
  • Versioning: Some databases support versioning, allowing different users to work on different versions of the same data
• Integration with Applications


  • APIs: Databases offer APIs for seamless integration with various applications, enabling data-driven functionalities
  • Data Exchange: Structured data formats in databases facilitate easy data exchange between different software systems
• Entity


  A definable thing or concept within a system, such as a person/role, object, concept or event
• Entity Attributes


  Properties or characteristics of the entity that hold it
• Primary Key


  A special kind of entity attribute that uniquely defines a record in a database table
• Foreign Key


  An attribute that is a reference to a primary key in a table, used to create relationships between tables
• Relationship


  An association between two entities
• Cardinality


  Defines the possible number of occurrences in one entity which is associated with the number of occurrences in another
• One-to-One Cardinality


  One occurrence of an instance of an entity in an entity set will have only a single occurrence of the same entity in another entity set
• One-to-Many Cardinality


  One occurrence of an instance of an entity in an entity set will have several occurrences of the same entity in another entity set
• Many-to-Many Cardinality


  Several occurrences of instances of entities in an entity set will have several occurrences of the same entities in another entity set
• Structured Query Language (SQL)

  A domain-specific language used in programming and managing relational database systems, allowing users to interact with databases, manipulate data, and retrieve information
• Uses of SQL


  • Data Manipulation
  • Data Retrieval
  • Data Modification
  • Data Definition
  • Data Control