Practice: Sequelize Seeders

In this short practice, you will be generating, running, and undoing seeder files with Sequelize.

Getting started

Download starter.

Execute the setup-commands.sh script from the root directory of this practice. View the contents of the script to see the commands that are executed, and view the results in the terminal to confirm that setup was successful.

sh setup-commands.sh

The Express endpoints for this practice will not yield results from a database but are included in order to demonstrate how to initialize Sequelize with an existing server. This can be seen from the plaintext responses given by these endpoints.

In future practices, you will utilize routes in order to interact with a connected database.

Step 1: Generate a seeder

Using Sequelize, you will be inserting the primary colors as seed data for the Colors table.

In the terminal within the server folder, use sequelize-cli to generate a new seeder. Name this migration primary-colors.

Step 2: Create a bulkCreate statement

Utilize the bulkCreate function of the Color model to define three values to be inserted into the Colors table. The migration provided for you indicates attributes for id, name, createdAt, and updatedAt. Since the id is autoincremented and the createdAt and updatedAt have default values, the only attribute needed to create a new entry is the name. Create entries for the following colors:

name
red
blue
yellow

Step 3: Create a bulkDelete statement

Utilize the bulkDelete function of the queryInterface to remove the colors that were created in the previous step. Do not simply delete all entries, be specific!

Hint: The second argument to bulkDelete is a WHERE clause. Multiple values can be provided as an IN condition by using an array [].

Step 4: Run the seeder and check the database

Use sequelize-cli to run the seeder. If the table hasn't been created in the database yet, you may have to first run the migration.

Check that the database contains the seed data using sqlite3 in the terminal. Run a simple SELECT query to see the contents of the Colors table.

You can test if you have implemented the up and down functions correctly by running npm test in the server directory.

Step 5: Undo the seeder and check the database

In the terminal within the server folder, use sequelize-cli to undo the seeder.

Check that the database no longer has the seed data defined in the seeder file.

Bonus Step 6: Seed more data

Using Sequelize, you will be inserting more colors as seed data for the Colors table.

Use sequelize-cli to generate a second seeder named fancy-colors. Create a bulkCreate and bulkDelete to add and remove a few more colors. In this seeder, define your own createdAt and updatedAt values. While this may not be the most practical in this scenario, it's good to see how you can overwrite default values. Create a new Date object with a specific date for each color that you create (any date will do, so use whatever date you like).

Use sequelize-cli to run both seeder files.

Check that the database contains the seed data of both files. Ensure that your custom dates were used for the fancy-colors while the default value (the current time) was used for the primary-colors.

Use sequelize-cli to undo the most recent seeder file.

Check that the database now only contains the data from the first seeder.

You can test if you have implemented the up and down functions in the second seeder correctly by running npm test test/bonus in the server directory.

Congratulations!

You are now able to generate, run, and undo seeder files with Sequelize.

Submission

Submit your work.

1. Delete the node_modules folder in the server directory
2. Zip up the project folder
3. Submit the zip file