강의/Database Systems3 2. Modern SQL Relational algebra is based on sets (unordered, no duplicates). SQL is based on bags (unordered, allows duplicates). SQL History SQL is comprised of different classes of commands: Data Manipulation Language (DML): SELECT, INSERT, UPDATE, and DELETE statements. Data Definition Language (DDL): Schema definitions for tables, indexes, views, and other objects. Data Control Language (DCL): Security, .. 2022. 11. 15. 1. Relational Model & Relational Algebra Database - an organized collection of inter-related data that models some aspects of the real-world (e.g., modeling the students in a class or a digital music store) DBMS (DataBase Management System) - a software that allows applications to store and analyze information in a database (e.g. MySQL, Oracle, MongoDB, Snowflake, ...) A general-purpose DBMS is designed to allow the definition, creatio.. 2022. 11. 14. 0. Preview Reference: CMU 15-445/645 (Fall 2022) Schedule - CMU 15-445/645 :: Intro to Database Systems (Fall 2022) Course schedule with slides, lecture notes, and videos. 15445.courses.cs.cmu.edu 2022. 11. 14. 이전 1 다음