This repository supports the article I wrote regarding creating data access models in Node.js.
If you'd like to examine and work with this example code, clone or download the repository. Then open a command prompt and change into the project directory. Then run the following commands:
npm install
npm run knex migrate:latest
This will install the required components. In this case that is only Knex.JS and SQLite3. SQLite is only used for demo purposes here. The article focuses on the src/models/_model.js file and how it might be used.
In short, our application services call the data models, and the data models extend the _model.js file. The services directory represents what a "real" application may look like, but is just a sample.
- Make sure the database is set up
npm run knex migrate:latest- Run the application
node src/index.js- Check your database
sqlite3 dev.sqlite3
select * from groups;
select * from tasks;This will result in output that looks something like the following. You can expect the timestamps to be different.
1|Group 1|1596959593881
sqlite> select * from tasks;
2|1|automated task|SOME RANDOM VALUE||This is an example task|1596959593908
sqlite>
To re-run the code, clear the database first. You can do this quickly by rolling back the database changes and then reapplying them
npm run knex migrate:rollback;
npm run knex migrate:latest
The _model.js file was created to work with application databases. For this example we use SQLite3, which is not really recommended for production projects.
The .returning() method provided by Knex.JS is not supported by SQLite. This prevents us from simply retrieving the inserted or updated records in the .create() and .update() methods in _model.js. The example code in index.js reflects this. However, if you were to switch to MySQL, Postgres, MSSQL, etc. then .returning() is supported and you would not need to do any extra steps. Drop me a note if this is confusing and I can alter the article or repo accordingly.