Database Access Layer (DBAL) is a wrapper for DynamoDB Client. It provides the basic create, read, update and delete (CRUD) functionality and lets you group data into an entity.
Install the Database Access Layer
npm i @growsari/dbal
Require or import the package as Entity
const Entity = require('@growsari/dbal')
Before we could use it, the project must have the following environment variables
ENV | Description | Default Value | Other Value |
---|---|---|---|
IS_OFFLINE | Flag for local development | false | true |
DB_ADAPTER | Database to be used | dynamodb | ~ |
DYNAMODB_ENDPOINT | DynamoDB endpoint | http://localhost:8000 | ~ |
TABLE_NAME | DynamoDB table name | ~ | ~ |
Create a new class and extend Entity
'use strict'
const Entity = require('@growsari/dbal')
class User extends Entity {
constructor() {
super()
this.attributes = {
email: [
'identifier'
],
group_id: [
'foreign'
]
}
this.sort = [
{
index: 'SortByCreatedAtIndex',
field: 'created_at'
},
{
index: 'SortByNameIndex',
field: 'name'
}
]
}
}
module.exports = User
Require User
entity and create item:
await User.create({
name: 'John Doe',
email: 'john.doe@example.com',
group_id: 'BDS45HX47I9CT'
})
// {
// "id": "659312a0-1b5c-11ea-a271-e732f3f9733b",
// "created_at": "2019-12-10T14:50:24.330Z",
// "updated_at": "2019-12-10T14:50:24.330Z",
// "name": "John Doe",
// "email": "john.doe@example.com",
// "group_id": "BDS45HX47I9CT"
// }
Read item by:
await User.getById('659312a0-1b5c-11ea-a271-e732f3f9733b')
Update item by:
await User.updateById('659312a0-1b5c-11ea-a271-e732f3f9733b', {
name: 'John Doe II'
})
Delete item by:
await User.deleteById('659312a0-1b5c-11ea-a271-e732f3f9733b"')
These are the properties for configuring an entity
Lets you configure a special field in an item which implies uniqueness, foreign key and so on
Value | Description |
---|---|
identifier | Creates a field with unique value within the entity |
foreign | Creates a foreign key (id in another microservice) |
namespace:field | Creates an identifier within a namespace (determined by field) |
Sample
this.attributes = {
[attribute_name] : [
'identifier',
'foreign',
'namespace:field'
]
}
List of DynamoDB global secondary indexes (GSI) for data retrieval sorting
These are the available functions for managing the data within an entity
async create(data)
async updateById(id, data)
async deleteById(id)
async bulkCreate(collection)
async bulkUpdate(collection)
async bulkDelete(collection)
async getById(id)
async getByIdOrFail(id)
async getByIdentifier(identifier, value)
async getByIdentifierWithinNamespace(namespace, identifier, value)
async getByIds(ids)
async getAll(first, after, sortBy, filterConditions)
async getAllByForeignKey(foreignKey, foreignValue, first, after, sortBy, filterConditions)
async search(query, rawQuery, fields, perPage, page, filters, sort)
async reindex()
async syncWithSearchEngine()
A string which is composed of field
name and order
joined by |
.
const sortBy = 'name|asc'
await Product.getAll(first, after, sortBy, filterConditions)
NOTE: To effeciently use the filter conditions in terms of DynamoDB RCU and WCU, I recommend using it with getAll() API. If you can't avoid using it with getAllByForeignKey() API please use filter with the defined sort fields.
These are the recognized compound expressions:
Asserts that all of the subexpressions' conditions are satisfied.
const filterConditions = [
'AND',
{ name: 'Coke' },
{ is_available: true },
// more subexpressions
]
await Product.getAll(first, after, sortBy, filterConditions)
The above condition is equivalent to the following boolean expression:
name === 'COKE' && is_available === true && ...
Asserts that at least one of the subexpressions' condtions are satisfied.
const filterConditions = [
'OR',
{ name: 'Coke' },
{ brand: 'Coke' },
// more subexpressions
]
await Product.getAll(first, after, sortBy, filterConditions)
The above condition is equivalent to the following boolean expression:
name === 'COKE' || brand === 'Coke' || ...
Asserts that at least one of the subexpressions' condtions are satisfied.
const filterConditions = [
'AND',
{ name: 'Coke' },
['NOT', { is_available: true }]
]
await Product.getAll(first, after, sortBy, filterConditions)
The above condition is equivalent to the following boolean expression:
name === 'COKE' && is_available !== true
An object with one pair of key and value. The object's key represents the field
name. The object's value is also an object and it represents the condition where the condition's key is the operation
.
==
operation creates a condtion which is true if the field
is equal to the defined value
.
const filterConditions = { name: { '==': 'Coke' } }
// can be simplified to:
// const filterConditions = { name: 'Coke' }
await Product.getAll(first, after, sortBy, filterConditions)
!=
operation creates a condtion which is true if the field
is not equal to the defined value
.
const filterConditions = { is_available: { '!=': false } }
await Product.getAll(first, after, sortBy, filterConditions)
<
operation creates a condtion which is true if the field
is less than to the defined value
.
const filterConditions = { available: { '<': 10 } }
await Product.getAll(first, after, sortBy, filterConditions)
<=
operation creates a condtion which is true if the field
is less than or equal to the defined value
.
const filterConditions = { available: { '<=': 10 } }
await Product.getAll(first, after, sortBy, filterConditions)
>
operation creates a condtion which is true if the field
is greater than to the defined value
.
const filterConditions = { available: { '>': 10 } }
await Product.getAll(first, after, sortBy, filterConditions)
>=
operation creates a condtion which is true if the field
is greater than or equal to the defined value
.
const filterConditions = { available: { '>=': 10 } }
await Product.getAll(first, after, sortBy, filterConditions)
between
operation creates a condtion which is true if the field
is between value[0]
and value[1]
.
const filterConditions = {
created_at: {
'between': ['2020-06-01T00:00:00.000Z', '2020-06-15T00:00:00.000Z']
}
}
await Product.getAll(first, after, sortBy, filterConditions)
in
operation creates a condtion which is true if the field
is equal to an element the defined set of value
s.
const filterConditions = {
tags: {
'in': ['bottle', 'soda', 'promo', 'top_10', 'drink']
}
}
await Product.getAll(first, after, sortBy, filterConditions)
NOTE! This operation will only work with sort fields
beginsWith
operation creates a condtion which is true if the field
is a string and begins with or has a prefix of value
.
const filterConditions = { status: { 'beginsWith': 'active_' } }
await Product.getAll(first, after, sortBy, filterConditions)
NOTE! This operation will only work with sort fields
contains
operation creates a condtion which is true if the field
contains the defined value
.
const filterConditions = { status: { 'contains': 'active' } }
await Product.getAll(first, after, sortBy, filterConditions)
Code | Message |
---|---|
DBAL-001 | Database not supported |
DBAL-002 | Item not found for 'entity' entity |
DBAL-003 | Invalid pagination cursor |
DBAL-004 | Identifier 'field' must be unique |
DBAL-005 | Identifier 'field' within the namespace 'field' must be unique |
DBAL-006 | Sort key 'field' is not provided |
DBAL-007 | Invalid value for foreign key 'field' |
DBAL-008 | Duplicate entries in array as input is not allowed |
DBAL-009 | Invalid search engine setup |