CS257 Software Design
Friday, 25 April 2025

+ Misc
- You'll get a blitz of grading emails from me over the weekend
- Midterm
    - Project described
    - Database designed and implemented/populated
    - API designed and implemented
- Post-midterm
    - Turn focus to user interface
    - HTML/CSS/Javascript

+ Questions

+ Database kickoff
- What's postgresql?
    a particular Database Management System (DBMS)
    software that manages & lets you interact with a database
- What's postgres?
    in practice: another, shorter name for postgresql
- What's a daemon, and how is that idea relevant to postgres?
    "daemon" = "server"; "server" is confusing sometimes--is it software or hardware?
    a process (i.e., a running program) that listens for requests
        and then fulfills those requests
    the postgres daemon waits for database requests
- What's SQL?
    query language for interacting with a database
    "structured query language"
    we're going to learn a tiny sliver of SQL, mostly SELECT statements
- What's psql?
    a client (i.e., client software) that can send queries to
        the postgres daemon
    handy for development and testing; mostly not used for applications
- Tables
    the basic unit of organization in an SQL database
    2-dimensional grids
    columns have names and types
- Queries
    SELECT * FROM authors
        show all fields/columns (*) for all rows in the authors table
    SELECT * FROM authors ORDER BY surname
    SELECT given_name, surname FROM authors ORDER BY surname
    SELECT given_name, surname FROM authors
        WHERE surname LIKE 'B%' ORDER BY surname
    ...

- Design principles for starters
    - think "what are my main thing types?" and give them each a table
        e.g., books & authors
        note: a book can have many authors; an author can have many books
            "many-to-many relationship"
    - how can I pick tables to eliminate duplicate data?

+ Lab: turning a messy CSV file into postgres tables

+ Have a good weekend!