2.1.3. Common Database Objects

💡 First Principle: Relational databases use specific object types to organize data, optimize access, and provide abstraction layers for users and applications. Each object type serves a distinct purpose in the database ecosystem.

• Tables: The primary storage structures containing rows and columns. Each row is a unique record, and each column is a specific attribute with a data type.
• Views: Virtual tables based on the result set of a SQL query. They don't store data themselves but provide a way to look at data from one or more tables, often used for security or simplifying complex queries.
• Indexes: Structures used to speed up retrieval of data. Think of it like the index at the back of a book; it allows the database engine to find rows without scanning the entire table.
• Stored Procedures: Precompiled collections of SQL statements stored in the database. They enable code reuse, security (granting access to logic without raw data), and reduced network traffic.

Visual: SQL Command Categories

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⚠️ Exam Trap: Confusing DDL and DML is heavily tested. DROP TABLE (DDL) deletes the structure. DELETE FROM Table (DML) removes rows but keeps the table. TRUNCATE TABLE (DDL) removes all rows instantly but keeps the structure.