Best ORM for Dgraph Database in Nodejs
Dgraph database is the Node-based database that is like an Object and has relations on edges. This is useful when your needs are not fulfilled in rows and column-based data structure. To use the Dgraph database in the Node.js you need an ORM to connect and manage the database.
DgraphORM is best suited to have all required methods to manage your Dgraph Database similar to Mongoose, Sequilize and etc. Here is the way to use it.
Installation
npm install dgraph-ormSample Schema
import dgraph from 'dgraph-orm';
const UserSchema = new dgraph.Schema('user', {
name: {
type: dgraph.Types.STRING,
index: true,
token: {
term: true
}
},
email: {
type: dgraph.Types.STRING,
index: true,
unique: true,
token: {
exact: true
}
},
password: dgraph.Types.PASSWORD,
bio: dgraph.Types.STRING,
friend: {
type: dgraph.Types.UID,
model: 'user', // related model name
count: true,
reverse: true
}
});
/**
* Set and create model out of the schema
*/
const User = dgraph.model(UserSchema);
Types
DgraphORM supports all the types supported in Dgraph
// uid
dgraph.Types.UID
// int
dgraph.Types.INT
// string
dgraph.Types.STRING
// float
dgraph.Types.FLOAT
// bool
dgraph.Types.BOOL
// datetime
dgraph.Types.DATETIME
// geo
dgraph.Types.GEO
// password
dgraph.Types.PASSWORD
Indexes
DgraphORM supports all the index types and tokenizers
import dgraph from 'dgraph-orm';
const UserSchema = new dgraph.Schema('user', {
name: {
type: dgraph.Types.STRING,
unique: true, // enable unique constraint on the field (only works with type STRING, INT and FLOAT)
list: true, // enable list type
count: true, // enable count on the field
lang: true, // enable lang type
index: true, // enable index
token: {
term: true, // enable term index tokenizer
fulltext: true, // enable fulltext index tokenizer
trigram: true // enable trigram index tokenizer
}
}
});
Different field type can have different type of indexes and tokenizers, please see Dgraph Documentation for the same.
Main methods
import dgraph from 'dgraph-orm';
/**
* connect
*
* Connect dgraph database
*/
dgraph.connect(host, port, credential);
/**
* model
*
* Generate model from schema
*/
dgraph.model(Schema);
/**
* logging
*
* set custom logger
*
* Default is console.log
*/
dgraph.logging(logger: function)
/**
* disconnect
*
* close database connection
*/
dgraph.disconnect();
/**
* original
*
* dgraph-js properties
*
* All properties from dgraph-js are also availble in the dgraph object
*
* Payload
* createPayload
* Response
* createResponse
* Mutation
* Operation
* Request
* Assigned
* TxnContext
* Check
* Version
* NQuad
* Value
* Facet
* SchemaNode
* LinRead
* Latency
* DgraphClientStub
* DgraphClient
* deleteEdges
* Txn
* ERR_NO_CLIENTS
* ERR_FINISHED
* ERR_ABORTED
*
* Check dgraph-js documentaion for more details
*
* https://github.com/dgraph-io/dgraph-js
*/
dgraph.original;
Model methods
The created model has methods to query the dgraph database
/**
* query
*
* dgraph's raw query
*/
User.query(query: String);
/**
* queryWithVars
*
* dgraph's raw query with varibales
*
* to know more visit
* https://docs.dgraph.io/master/query-language/#graphql-variables
*
*/
User.queryWithVars(params = {
query: String,
variables: {}
});
/**
* create
*
* dgraph's create mutation
*
*/
User.create({
field_name: value
});
/**
* update
*
* dgraph's update mutation
*
*/
User.update({
field_name: value
}, {
field: value
} or uid: String);
/**
* delete
*
* dgraph's delete mutation
*
*/
User.delete(uid: String);
// Delete multiple uids
User.delete([uid1: String, uid2: String]);
/**
* checkPassword
*
* dgraph's checkpwd query
*
* Note: A field type PASSWORD
*
*/
User.checkPassword(uid: String, field: string, password: String);
/**
* has
*
* dgraph has root method to query nodes
*/
User.has(field_name: String, options);
/**
* eq
*
* dgraph eq root method to query nodes
*/
User.eq(field_name: String, value: String, options);
/**
* uid
*
* dgraph's uid root method to query nodes
*/
User.uid(uid_value: String | String[], options);
/**
* allofterms
*
* dgraph's allofterms root method to query nodes
*
*/
User.allofterms(field: String, value: String, options);
/**
* anyofterms
*
* dgraph's anyofterm root method to quert nodes
*/
User.anyofterms(field: String, value: String, options);
/**
* anyoftext
*
* dgraph's anyoftext root method to query nodes
*/
User.anyoftext(field: String, value: String, options);
/**
* alloftext
*
* dgaph's alloftext root method to query nodes
*/
User.alloftext(field: String, value: String, options);
/**
* regexp
*
* dgraph's regexp method to query nodes
*/
User.regexp(field: String, regex: String, options);
/**
* near
*
* dgraph's near root method to query nodes
*
* Note: only works with geo type predicate
*/
User.near(field: String, value = {
latitude: float,
longitude: float
distance: number
}, options);
/**
* contains
*
* dgraph's contains root method to query nodes
*
* Note: only works with geo type predicate
*/
User.contains(field: String, value = {
latitude: float,
longitude: float
}, options);
Options
Every model method accepts options to filter, paginate and order the nodes
// Simple filtering
// retrive all nodes having user.name and user.email 'akvlko@gmail.com'
User.has('name', {
filter: {
email: {
$eq: 'akvlko@gmail.com'
}
}
});
// OR condition
// retrives all the nodes having user.name where user.email is 'akvlko@gmail.com' or user.name is 'Ashok'
User.has('name', {
filter: {
$or: {
name: {
$eq: 'Ashok'
},
email: {
$eq: 'akvlko@gmail.com'
}
}
}
});
// Specific Attributes
// retrives all the nodes having user.name with their name and email only
// PS: by default fetches all the fields defined in the schema (exepct relations) if attributes property is not given.
User.has('name', {
attribute: ['name', 'email']
});
// Single Order
// retrives all the nodes having user.name and order them by user.email ASC
User.has('name', {
order: ['email', 'ASC']
});
// Multiple order
// retrives all the nodes having user.name and order them user.name ASC and user.email DESC
User.has('name', {
order: [['name', 'ASC'], ['email', 'DESC']]
});
// Pagination
// Retrives 10 nodes having user.name skipping first 5 after 0.x25 uid
User.has('name', {
first: 10,
offset: 5,
after: '0x25'
});
// Quering Relation
// Retrives all the nodes haing user.name along with count of their friend as friends
User.has('name', {
include: {
freind: {
count: true,
as: 'freinds'
}
}
});
// Full options in relation
User.has('name', {
include: {
friend: {
as: 'freinds',
filter: {}, // accept a filter like the above example
attributes: ['name', 'email'], // accepts attributes like the abobe example
order: [], // accepts order like the above example
first: 10, // accepts first
offset: 2, // accepts offset
after: '0x21' // accepts after
}
}
});
Create
Create an example using a model
// Create
/**
* Creates a new user with passed fields
*
* Returns the created user along with the generated uid
*/
const user = await User.create({
name: 'Ashok Vishwakarma',
email: 'akvlko@gmail.com',
bio: 'My bio ...'
});
console.log(user);
// {
// uid: '0x1',
// name: 'Ashok Vishwakarma',
// email: 'akvlko@gmail.com',
// bio: 'My bio ...'
// }
Update
Update example using model
/**
* Recommended
*
* using uid
*/
User.update({
name: 'Ashok Kumar Vishwakarma',
}, '0x1');
/**
* Not Recommended
*
* using field
* Using field will update the first users matching with the field values
*/
User.update({
name: 'Ashok Kumar Vishwakarma',
}, {
email: 'akvlko@gmail.com'
});
Delete
Delete example using model
PS: Delete only support <uid> * * pattern, which means all the related predices will be deleted
/**
* single user
*
* Will delete the user having uid 0x1
*/
User.delete('0x1');
/**
* multiple users
*
* Will delete the users having uid 0x1 and 0x2
*/
User.delete(['0x1', '0x2']);
/**
* Delete property for single user
*
* Will delete user.name from uid 0x1
*/
User.delete({
name: null
}, '0x1');
/**
* Delete property for mutliple user
*
* Will delete user.name from uid 0x1 and 0x2
*/
User.delete({
name: null
}, ['0x1', '0x2']);
Relations
Add relation values
/**
* Single
*
* Will add 0x2 as a friend of 0x1
*/
await User.update({
friend: '0x2'
}, '0x1');
/**
* multiple
*
* Will add 0x2, 0x3 as freinds of 0x1
*/
await User.update({
friend: ['0x2', '0x3']
}, '0x1');
Delete Relation
/**
* Single
*
* Will remobe 0x2 from 0x1 freiends
*/
await User.delete({
friend: '0x2'
}, '0x1');
/**
* multiple
*
* Will remove 0x2, 0x3 from 0x1 freinds
*/
await User.delete({
friend: ['0x2', '0x3']
}, '0x1');
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