coriagogo / webdb-i-challenge

Web DB I Module Challenge

SQL Exercises

Topics

• Structured Query Language (SQL)
• Relational Databases
• SQLite
• Writing Basic Queries

Assignment

For this lab you will:

• write SQL statements against a pre-populated database using an online tool. Once you have the correct SQL Statement for each query, write it inside the queries.md file under the appropriate heading.
• install SQLite Studio and use it to create a database within this codebase.
• using SQLite Studio add a table to the database you just created.
• write API endpoints to interact with your database

Write Basic Queries

Visit SQL Try Editor at W3Schools.com using the Google Chrome (or Chromium if you use Linux) browser and write SQL queries for the following requirements:

• find all customers that live in London. Returns 6 records.
• find all customers with postal code 1010. Returns 3 customers.
• find the phone number for the supplier with the id 11. Should be [phone].
• list orders descending by the order date. The order with date 1997-02-12 should be at the top.
• find all suppliers who have names longer than 20 characters. You can use length(SupplierName) to get the length of the name. Returns 11 records.
• find all customers that include the word "market" in the name. Should return 4 records.
• add a customer record for "The Shire", the contact name is "Bilbo Baggins" the address is "1 Hobbit-Hole" in "Bag End", postal code "111" and the country is "Middle Earth".
• update Bilbo Baggins record so that the postal code changes to "11122".

Clicking the Restore Database button in the page will repopulate the database with the original data and discard all changes you have made.

Create Database and Table

• use SQLite Studio to create a database, name it budget.db3 and save it in the data folder of this repository. You must use this exact name and save it within the data folder or your accounts-model will not be able to connect.

• add an accounts table with the following schema:

  • id, numeric value with no decimal places that should auto-increment.
  • name, string
  • budget numeric value.

• constraints

  • the id should be the primary key for the table.
  • account name should be required and unique.
  • account budget is required.

Database Access

Database access will be done using the accounts-model.js file included inside the data folder. This file publishes the following methods:

All these methods are asynchronous and return a promise.

• find(): calling find returns a promise that resolves with an array of all the accounts contained in the database.
• findById(): this method expects an id as it's only parameter and returns a promise that resolves with the account corresponding to the id provided or a falsy value if an account with that id is not found.
• add(): calling add passing it a account object will add it to the database and return a promise that resolves with the newly inserted account.
• update(): accepts two arguments, the first is the id of the account to update and the second is an object with the changes to apply. It returns a promise that resolves with the count of updated records. If the count is 1 it means the record was updated correctly.
• remove(): the remove method accepts an id as it's first parameter and upon successfully deleting the account from the database it returns returns a promise that resolves with the number of records deleted.

Now that we have a way to add, update, remove and retrieve data from the provided database, it is time to work on the API.

Write endpoints for the accounts resource

• Within server.js add CRUD endpoints for the account resource. You may use data/accounts-model.js for access to your newly created database. The methods included in the accounts-model are described above in the Database Access section.
• Use these endpoints to manually test that your database is working as expected.

Stretch Problems

The following exercises require research, the concepts needed to complete them have not been covered in class yet.

• delete all customers that have no orders. Should delete 18 records.
• list orders grouped by customer showing the number of orders per customer. Rattlesnake Canyon Grocery should have 7 orders.
• list customers names and the number of orders per customer. Sort the list by number of orders in descending order. Ernst Handel should be at the top with 10 orders followed by QUICK-Stop, Rattlesnake Canyon Grocery and Wartian Herkku with 7 orders each.
• list orders grouped by customer's city showing number of orders per city. Returns 58 Records with Aachen showing 2 orders and Albuquerque showing 7 orders.