herbs2knex creates repositories to retrieve and store Entities using Knex.
$ npm install @herbsjs/herbs2knex
connection.js - Knex initialization:
const knex = require('knex')
const config = require('./config')
module.exports = knex(config)itemRepository.js:
const { Repository } = require('@herbsjs/herbs2knex')
const connection = require('connection')
const { Item } = require('../domain/entities/item')
class ItemRepository extends Repository {
constructor() {
super({
entity: Item,
table: 'aTable',
ids: ['id'],
knex: connection
})
}
excludedItemFromLastWeek() {
...
}
}someUsecase.js:
const repo = new ItemRepository()
const ret = await repo.findByID(1)A repository, by definition, is part of the layer to retrieve and store entities abstracting the underlying implementation. By using repositories, details of these implementation such as relational database, document-oriented databases, etc, should not leak to the domain code. In other words, no raw SQL queries on your use case or entity files.
In order to boost productivity Herbs2knex provides way to dynamically generate a repository class based on your Entities and other metadata.
These metadata are necessary to close the gap between OOP concepts and paradigms and those of relational databases. For example, it is necessary to specify primary keys and foreign keys as these information do not exist in the description of your domain.
Following Herbs architecture principals it is not the intention of this lib to create yet another ORM or query builder but to create a bridge between your domain and an existing one (Knex).
Herbs2knex is just one of many bridges possible between Herbs and other packages.
The advantage of using Knex is that is a simple and flexible SQL query builder. It also supports Postgres, MSSQL, MySQL, MariaDB, SQLite3, Oracle, and Amazon Redshift. So you can build your system using these databases out of the box.
const { Repository } = require('@herbsjs/herbs2knex')
const connection = require('connection') // Knex initialize instance
const { ProductItem } = require('../domain/entities/productItem')
class YourRepository extends Repository {
constructor() {
super({
entity: ProductItem,
schema: 'main',
table: 'product_items',
ids: ['id'],
foreignKeys: [{ customerId: String }],
knex: connection
})
}
}-
entity- The Entity to be used as referenceentity: ProductItem -
schema- The schema to be usedschema: 'production' -
table- The name of the table in databasetable: 'product_items' -
ids- Primary keysFormat:
['fieldName', 'fieldName', ...]There must be corresponding fields in the entity.
ids: ['id'] // productItem.id
or for composite primary key:
ids: [`customerId`, `productId`] // productItem.customerId , productItem.productId
-
foreignKeys(optional) - Foreign keys for the database tableUsually there is no corresponding fields declared in the entity for foreign keys. That is the reason it is necessary to inform the name and the type of the fields.
Format:
[{ fieldName: Type }, { fieldName: Type }, ...]foreignKeys: [{ customerId: String }]
The field names will converted to a database names using conventions. Ex:
customer_id -
knex- Knex initialize instanceCheck Knex documentation
Find entities matched by the filter, or empty array [] if there is no matching entity.
Format: .find(options) where options is a optional object containing { limit, offset, orderBy, where }
Return: Entity array
const repo = new ItemRepository(injection)
const ret = await repo.find()Options:
limitAdds a limit clause to the query.
const repo = new ItemRepository(injection)
const ret = await repo.find({ limit: 10 })offsetAdds an offset clause to the query.
const repo = new ItemRepository(injection)
const ret = await repo.find({ offset: 5 })orderByAdds an order by clause to the query. Column can be string, or list mixed with string and object.
// order by collum
const repo = new ItemRepository(injection)
const ret = await repo.find({ orderBy: 'description'})
// order by complex query
const repo = new ItemRepository(injection)
const ret = await repo.find({ orderBy: [{ column: 'nome', order: 'desc' }, 'email'] })whereAdds a filter to the query with given values.
const repo = new ItemRepository(injection)
const ret = await repo.find({ where: { name: ["Anne"] } })Find entities by IDs
Format: .findByID(id) where id is a value or an array.
Return: Entity array
const repo = new ItemRepository(injection)
const ret = await repo.findByID(10)Finds the first entity matched by the filter, or empty array [] if there is no matching entity.
Format: .first(options) where options is a optional object containing { orderBy, where }
Return: Entity
const repo = new ItemRepository(injection)
const ret = await repo.first({ orderBy: 'description'})Insert an Entity into a table.
Format: .insert(entity) where entity is a Entity instance with values to be persisted.
Return: The inserted entity with the values from database.
const repo = new ItemRepository(injection)
const ret = await repo.insert(aNewEntity)Update an Entity.
Format: .update(entity) where entity is a Entity instance with values to be persisted.
Return: The updated entity with the values from database.
const repo = new ItemRepository(injection)
const ret = await repo.update(aModifiedEntity)Delete an Entity.
Format: .delete(entity) where entity is a Entity instance to be deleted.
Return: true for success or false for error
const repo = new ItemRepository(injection)
const ret = await repo.delete(entity)Code: Camel Case - ex: productName
Database: Snake Case - ex: product_name
You can use the custom convention to configure the way herbs2knex creates your queries to read fields from your database. When using this option, the ids property must respect the format convention.
const toCamelCase = value => camelCase(value)
const userRepository = new UserRepository({
entity: User,
table,
schema,
ids: ['id'],
knex: connection,
convention: {
toTableFieldName: field => toCamelCase(field)
}
})An entity can define a reference for others entities but will not (and should not) define a foreign key. For instance:
+------------------+ +------------------+ +------------------+
| Orders | | OrderItems | | Products |
+------------------+ +------------------+ +------------------+
| id: int |----\ | id: int | --| id: int |
| customer_id: int | ----| order_id: int | ----/ | name: string |
+------------------+ | product_id: int |-/ +------------------+
+------------------+
const Product = entity('Product', {
id: field(Number),
name: field(String),
...
})
const OrderItem = entity('Order Items', {
id: field(Number),
product: field(Product), // optional
...
})
const Order = entity('Order', {
id: field(Number),
item: field([OrderItem]), // optional
...
})More about: https://en.wikipedia.org/wiki/Object%E2%80%93relational_impedance_mismatch
- Allow only scalar types for queries (don't allow entity / object types)
- Allow to ommit schema's name
Features:
- Be able to change the conventions (injection)
- Exclude / ignore fields on a sql statement
- Awareness of created/updated at/by fields
- Plug-and-play knex
- Easy access knex structure
Retrieving and Persist:
- insert
- batchs
- update
- batchs
- delete
- persist (upsert)
- find (ID)
- deal with entities / tables with multiples IDs
- find by (any field)
- deal with entities / tables with multiples IDs
- order by
- find All
- order by
- find with pages
- first
Tests:
- Pure JS
- Postgress
- Sql Server
- MySQL
- Sqlite
Come with us to make an awesome herbs2knex.
Now, if you do not have technical knowledge and also have intend to help us, do not feel shy, click here to open an issue and collaborate their ideas, the contribution may be a criticism or a compliment (why not?)
If you would like to help contribute to this repository, please see CONTRIBUTING
herbs2knex is released under the MIT license.