Database Systems and Data Management

Study Notes

Data refers to raw, unorganized facts that require processing to become meaningful.
Types of data include facts, observations, numbers, characters, symbols, and images.
Information is processed data transformed into a meaningful format that serves specific user needs.

A database is a structured collection of related data for efficient storage, retrieval, and management.
Examples of databases include phone books, shopping lists, to-do lists, and user bases on social media.
Databases can be simple, like a single file, or complex with multiple interconnected tables.

A file system manages how data is stored, accessed, and managed on storage disks.
Common drawbacks include:
- Data redundancy and inconsistency.
- Difficulty accessing data.
- Data isolation issues.
- Integrity problems and atomicity of updates.
- Security concerns and challenges with concurrent access by multiple users.

A database system consists of a database (DB), database Management System (DBMS), and application programs.
It serves as a computerized record-keeping system and acts as a repository for computerized data files.
Main components include:
- Data: The actual information stored.
- Hardware: Physical devices used for storage and processing.
- Software: The applications that manage and manipulate data.
- User: Individuals who interact with the database system.

Data is organized in databases as tables, which are collections of related data entries.
A table is structured with columns (fields) and rows (records).

Each table is divided into fields, which are specific columns that hold particular information about each record.
For example, a CUSTOMERS table may include fields like ID, NAME, AGE, ADDRESS, and SALARY.

A record, also known as a row of data, represents an individual entry within a table.
Each row in a table contains specific data according to the defined fields, forming a complete record.