Database Fundamentals Why Learn Databases? Previously, to store data permanently, we used I/O streams to write data to local files. However, tasks like changing a specific user's age in a text file were cumbersome, requiring reading lines, creating objects, modifying them, and writing back. Database...
Core Concepts of Structured Query Language Structured Query Language (SQL) serves as the universal interface for interacting with relational databases. Its capabilities extend beyond simple queries to encompass schema definition, data manipulation, security enforcement, and integrity control. This m...
Table Definition Syntax CREATE TABLE table_name ( column1 data_type constraint, column2 data_type constraint ); Column Naming Convensions Avoid using numeric-only identifiers. Special characters are prohibited. Recommended practice: Use descriptive, snake_case names like employee_id or department_na...
Genarel SQL Syntax Rules SQL statements can span single or multiple lines, terminating with a semicolon Whitespace and indentation improve readability without affecting execution MySQL is case-insensitive for keywords (though uppercase is conventional) Comment syntax: Single-line: -- comment or # co...
Data Definition Language (DDL) DDL encompasses commands used to define and modify database schema structures. These operations affect the organization and properties of database objects rather than the data itself. Key commands include: CREATE: Establishes new database objects ALTER: Modifies existi...
This article provides a detailed walkthrough of Hive SQL, categorizing its features and syntax for practical use. Hive SQL is segmented into the following categories: DDL Statements: Operations on databases, including their creation, modification, viewing, and deletion. Table operations such as mani...