COSCUP 2019 - The discussion between Knex.js and PostgreSQL
3 likes402 views
This document discusses using knex.js to solve schema change problems. Knex.js is a SQL query builder that can be used with Node.js and relational databases. It features query building, pooling, transactions, migrations, and seed files. Migrations allow defining schema changes, and seed files populate data. Testing, automatic deployment, and using only JavaScript helps avoid crashes during schema updates and reduces operation errors.
![▪ Query Builder
▪ The heart of the library, the knex query builder is the interface used for building and
executing standard SQL queries, such as select, insert, update, delete.
▪ Example
knex({ a: 'table', b: 'table' })
.select({
aTitle: 'a.title',
bTitle: 'b.title'
})
.whereRaw('?? = ??', ['a.column_1', 'b.column_2’])
// select "a"."title" as "aTitle", "b"."title" as "bTitle" from "table" as "a", "table" as "b" where "a"."column_1" = "b"."column_2"
6](https://image.slidesharecdn.com/cuscpon2019-190817182649/85/COSCUP-2019-The-discussion-between-Knex-js-and-PostgreSQL-6-320.jpg)
Ad
More Related Content
What's hot (20)
Similar to COSCUP 2019 - The discussion between Knex.js and PostgreSQL (20)
Ad
More from Len Chang (8)
Ad
Recently uploaded (20)
COSCUP 2019 - The discussion between Knex.js and PostgreSQL
- 2. ▪ Me ▪ The introduction of knex.js ▪ What’s the problem that schema change ? ▪ Create seed data and migration files ▪ How to solve the problem ? ▪ Integrate it with Bitbucket pipeline ▪ Q & A 2
- 3. ▪ Len Chang ▪ Engineer ▪ Like.. ▪ Baseball / Beer / Finance ▪ Coding ▪ JavaScript / Typescript ▪ DB ▪ PostgreSQL / Elasticsearch ▪ Volunteer ▪ Nantou Code Geek ▪ You can find me.. ▪ LinkedIn ▪ Facebook ▪ PPT Online 3
- 5. ▪ Knex.js is a "batteries included" SQL query builder for Postgres, MSSQL, MySQL, MariaDB, SQLite3, Oracle, and Amazon Redshift designed to be flexible, portable, and fun to use. ▪ Basically it’s the major choice when you use nodejs and RDBMS to do the backend server. ▪ Features ▪ Query Builder ▪ Pooling ▪ Transactions ▪ Migrations ▪ Seed files 5
- 6. ▪ Query Builder ▪ The heart of the library, the knex query builder is the interface used for building and executing standard SQL queries, such as select, insert, update, delete. ▪ Example knex({ a: 'table', b: 'table' }) .select({ aTitle: 'a.title', bTitle: 'b.title' }) .whereRaw('?? = ??', ['a.column_1', 'b.column_2’]) // select "a"."title" as "aTitle", "b"."title" as "bTitle" from "table" as "a", "table" as "b" where "a"."column_1" = "b"."column_2" 6
- 7. Application ▪ Pooling ▪ The client created by the configuration initializes a connection pool, using the tarn.js library. This connection pool has a default setting of a min: 2, max: 10 7 Pooling Action Action Action PG Application Action Action Action PG
- 8. ▪ Transactions ▪ All queries within a transaction are executed on the same database connection, and run the entire set of queries as a single unit of work. Any failure will mean the database will rollback any queries executed on that connection to the pre-transaction state. ▪ Methods 1. As a transaction object 2. As a query builder 8 as a transaction object
- 9. ▪ Transactions ▪ Methods 1. As a transaction object 2. As a query builder 9 as a transaction object
- 10. ▪ Migrations ▪ Migrations allow for you to define sets of schema changes so upgrading a database is a breeze. 10
- 11. ▪ Seed files ▪ Seed files allow you to populate your database with test or seed data independent of your migration files. 11 Run seed
- 12. 12
- 13. Testing 1. How to avoid crashing when you update schema ? ▪ Testing 2. How to avoid operation error ? ▪ Deploy system automatically 13 DB (version + 1) Script: Updating schema Success (Commit) Failed (Rollback) DB (version + 1) DB (version) Dev DB Script: Updating schema QA DB PROD DB Dev DB Dev DB QA DB Script: Updating schemaScript: Updating schema
- 14. 3. Doesn’t need to use another tool or code language to do it. ▪ Just JavaScript 14
- 15. ▪ Summary ▪ How to avoid crashing when you updated schema ? ▪ Testing ▪ How to avoid operation error ? ▪ Deploying system automatically ▪ Doesn’t need to use another tool or code language to do it ▪ Just JavaScript 15
- 16. 16
- 17. ▪ Migration 1. knex init => knexfile.ts 17
- 18. ▪ Migration 2. knex migrate:make migration ▪ Up / Down Functions 18
- 19. ▪ Migration 3. knex migrate:latest 19 Check migration record Run unrecorded files
- 20. ▪ Migration Process 20 knexfile.ts 20190814170951_migration.ts Success (Commit)Failed (Rollback) Run Migration
- 21. ▪ Seed data 1. knex init => knexfile.ts 21
- 22. ▪ Seed data 2. Create seed data 22
- 23. ▪ Seed data 3. Create seed handling script and Running 23
- 24. ▪ Seed Process 24 Seed data of tables Seed handling Scripts knex seed:run DB
- 25. Testing, deploying system automatically and just javascript ! 25
- 26. ▪ Testing ▪ Embedded seed testing in migration Process 26 Transaction Transaction
- 27. ▪ Testing ▪ Dividing Environment ▪ All migration script is knex migrate:latest, but it run different script by different env. 27
- 28. ▪ deploying system automatically 28
- 29. ▪ Just javascript ▪ …well…. Just you said that….only javascript. 29
- 30. 30
- 31. 31
- 32. ▪ Advantage ▪ Reduce operation error ! ▪ Deploy schema simpler and safer. ▪ Do it by JS developer. 32