https://docs.google.com/document/d/1mfDaU3RW89WA3wJfRH1hGdGddWOhofMP/edit?usp=sharing&ouid=112711162618141236570&rtpof=true&sd=true
This document thoroughly explains database concepts, focusing on Database Management Systems (DBMS), Structured Query Language (SQL), and PHP connectivity.
- Database Fundamentals: The document defines a database as an organized collection of electronic data and a DBMS as the software that manages it. It covers types like Relational (RDBMS) and NoSQL, core terms such as Primary Key and Foreign Key, and principles like Normalization to reduce redundancy.
- Data Integrity & Control: Reliability is ensured by ACID Properties (Atomicity, Consistency, Isolation, Durability) for transactions.
- SQL Commands: SQL is categorized into DDL (structure definition), DML (data manipulation), DCL (access control), and TCL (transaction management). It details SQL operations like Joins (INNER, LEFT, RIGHT, FULL) and constraints.
- Data Structure: The document outlines various Data Types (Numeric, String, Date/Time) and explains Indexing as a tool to speed up data retrieval, noting the trade-off of increased storage use.
- Connectivity: Finally, it compares two PHP extensions—MySQLi and PDO—for connecting to and performing CRUD (Create, Read, Update, Delete) operations on a MySQL database, with PDO being recommended for multi-database or larger applications.
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