1. Data and Databases

1.1 Data

• Definition: Recorded or observable facts (e.g., age, address, height)
• Characteristics: Ubiquitous and voluminous
• Challenge: Efficient and effective storage on computers

1.2 Database (DB)

• Definition: Non-redundant, persistent collection of logically related records/files
• Purpose: Structured to support various processing and retrieval needs

1.3 Database Management System (DBMS)

• Definition: Software programs for creating, storing, updating, and accessing DB data
• Key difference from other programming systems: Ability to manage persistent data
• Primary goal: Provide convenient, efficient, and robust environment for data retrieval and storage
• Additional capabilities:
  • Data modeling
  • High-level languages for data definition, access, and manipulation
  • Transaction management and concurrency control
  • Access control
  • Recovery

2. Data Abstraction

2.1 Concept

• Simplifying or hiding data details based on user needs

2.2 Levels of Abstraction (lowest to highest)

1. Physical/Internal Level: Actual data storage on disk/cloud
2. Logical/Conceptual Level: Schema, actual stored data