1. Information Storage

✅ Files

• storage unit

✔️ File type: time-based

• 1️⃣ Temporary file
• 2️⃣ Permanent file

✔️ File type: content-based

• 1️⃣ Plain text: determined char encoding, text editor⭕️, txt
• 2️⃣ Binary: for application processing, text editor❌, application documents

✔️ Access methods

• 1️⃣ Sequential: consecutive location
• 2️⃣ Direct access/random/relative: each data is of fixed size
• 3️⃣ Indexed: external files sort the data

✅ Data Model

• structure of the DB
• could mean 1️⃣ abstract formalization 2️⃣ set of concepts(entity, attribute, relation)
• example: relation model

✔️ Data model type

• 1️⃣ Hierarchical: tree(single parent, one to many), pointer
• 2️⃣ Network: tree with many to many
• 3️⃣ Relational: table, attribute, domain
• 4️⃣ Object oriented
• 5️⃣ Object relational
• 6️⃣ Non-relational: NoSQL

✔️ Data model type: location

• 1️⃣ centralised
• 2️⃣ distributed

✅ DBMS

• program to organize/restore/retrive data efficiently and effecively

✔️ Components of DBMS

• data
• data access tools
  • programming language: create/read/modify data
  • data dictionary: metadata
  • CLI