#object relational mapping

In an online office furniture system, handling data efficiently is crucial for managing products, orders, and customers. Using an ORM like Eloquent in Laravel simplifies database interactions by allowing developers to work with objects instead of raw SQL queries.

For example, retrieving all products in a category can be done with $category->products instead of writing complex SQL joins. This makes the code more readable, maintainable, and secure, reducing the risk of errors and SQL injection.

So, you can also leverage Eloquent powerful features, such as relationships and query builders, developers can build scalable and efficient applications while keeping the codebase clean and organized.

Topics

ORM - Object Relational Mapping

Build our own from scratch

SQLite3 - serverless, can only run 1 query at a time, only good for small scale apps

Creating a SQL database from an import_db.sql file

Seeding a DB using INSERT INTO in import_db.sql file

SQLite3::Database - setting up & using a SQLite3 DB connection

Heredocs - doesn’t matter what you put after <<-, will start on following line and end once it meets the same string as starter

QuestionsDatabase.instance.execute(<<-SQL)

Treats entire block as a string

Can use interpolation #{}

Projects

AA Questions

a/A Application to help handle questions from students

Users table

Questions table

Question_follows table

Replies table

Question_likes table

QuestionsDatabase class < SQLite3::Database

include Singleton module

self.type_translation = true – maintains original type of input/values

self.results_as_hash = true – can set results via hash

Wrote a ton of class methods to pull relationships, save instances to the DB, set relationships, etc.

class ModelBase that other models inherit, to modularize ::find_by_id(id), ::all, and #save methods

class Question < ModelBase

Seems similar to what ActiveRecord does (tomorrow’s project)

Methods that ActiveRecord has that are similar/identical to the ones we built

::new #name = " " #save ::first ::all ::last #destroy ::find(id) ::find_by(key: value) ::create(key1: value1, key2: value2)

7. Partner: Ken Cha * Finished entire project, half of the bonus problems

Learnings

cat import_db.sql | sqlite3 questions.db - command to create DB

gem ‘sqlite3’ - must include in Gemfile to use sqlite3

Became more comfortable writing SQL queries using heredocs

Use class methods to write instance methods

Joseph Kim knows Javascript

Matt Corley - can write code blocks using < pre > < code > Put code block here!!! < / code > < / pre > to write code blocks on separate lines on Tumblr

Dawn Tran-Kiem uses memes in her a/A blog posts. They are hilarious.

Samuel Lyons is following my blog – W00T!!!

If you want to build up a SQL query as a string and then include it as an argument in a SQLite3::Database.instance.execute(query) method, must include ’ around string values, otherwise will throw error

SQLite3::Database.instance methods

#execute - will return an array of rows (hashed data)

#get_first_row - will return only first row