Introduction
Objection.js is an ORM for Node.js
that aims to stay out of your way and make it as easy as possible to use the full power of SQL and the underlying
database engine.
Objection.js is built on the wonderful SQL query builder knex. All databases supported by knex
are supported by objection.js. SQLite3, Postgres and MySQL are thoroughly tested.
What objection.js gives you:
What objection.js doesn't give you:
- A custom query DSL. SQL is used as a query language.
- Automatic database schema creation and migration.
It is useful for the simple things, but usually just gets in your way when doing anything non-trivial.
Objection.js leaves the schema related things to you. knex has a great migration tool
that we recommend for this job. Check out the example project.
Objection.js uses Promises and coding practices that make it ready for the future. We use Well known
OOP techniques and ES6 compatible classes and inheritance
in the codebase. You can even use things like ES7 async/await
using a transpiler such as Babel. Check out our ES6
and ES7 example projects.
Topics
Installation
npm install knex objection
You also need to install one of the following depending on the database you want to use:
npm install pg
npm install sqlite3
npm install mysql
npm install mysql2
npm install mariasql
Getting started
To use objection.js all you need to do is initialize knex and give the
connection to objection.js using Model.knex(knex)
:
var Knex = require('knex');
var Model = require('objection').Model;
var knex = Knex({
client: 'postgres',
connection: {
host: '127.0.0.1',
database: 'your_database'
}
});
Model.knex(knex);
The next step is to create some migrations and models and start using objection.js. The best way to get started is to
use the example project:
git clone git@github.com:Vincit/objection.js.git objection
cd objection/examples/express
npm install
npm install knex -g
knex migrate:latest
npm start
The express
example project is a simple express server. The example-requests.sh
file contains a bunch of curl
commands for you to start playing with the REST API.
cat example-requests.sh
If you are using a newer version of Node and you want to use ES6 features then our
ES6 version of the example project
is the best place to start.
We also have an ES7 version of the example project
that uses Babel for ES7 --> ES5 transpiling.
Also check out our API documentation and recipe book.
Query examples
The Person
model used in the examples is defined here.
All queries are started with one of the Model methods query(),
$query() or $relatedQuery().
All these methods return a QueryBuilder instance that can be used just like
a knex QueryBuilder.
Insert a person to the database:
Person
.query()
.insert({firstName: 'Jennifer', lastName: 'Lawrence'})
.then(function (jennifer) {
console.log(jennifer instanceof Person);
console.log(jennifer.firstName);
console.log(jennifer.fullName());
})
.catch(function (err) {
console.log('oh noes');
});
insert into "Person" ("firstName", "lastName") values ('Jennifer', 'Lawrence')
Fetch all persons from the database:
Person
.query()
.then(function (persons) {
console.log(persons[0] instanceof Person);
console.log('there are', persons.length, 'Persons in total');
})
.catch(function (err) {
console.log('oh noes');
});
select * from "Person"
The return value of the .query()
method is an instance of QueryBuilder
that has all the methods a knex QueryBuilder has. Here is a simple example that uses some of them:
Person
.query()
.where('age', '>', 40)
.andWhere('age', '<', 60)
.andWhere('firstName', 'Jennifer')
.orderBy('lastName')
.then(function (middleAgedJennifers) {
console.log('The last name of the first middle aged Jennifer is');
console.log(middleAgedJennifers[0].lastName);
});
select * from "Person"
where "age" > 40
and "age" < 60
and "firstName" = 'Jennifer'
order by "lastName" asc
The next example shows how easy it is to build complex queries:
Person
.query()
.select('Person.*', 'Parent.firstName as parentFirstName')
.join('Person as Parent', 'Person.parentId', 'Parent.id')
.where('Person.age', '<', Person.query().avg('Person.age'))
.whereExists(Animal.query().select(1).whereRef('Person.id', 'Animal.ownerId'))
.orderBy('Person.lastName')
.then(function (persons) {
console.log(persons[0].parentFirstName);
});
select "Person".*, "Parent"."firstName" as "parentFirstName"
from "Person"
inner join "Person" as "Parent" on "Person"."parentId" = "Parent"."id"
where "Person"."age" < (select avg("Person"."age") from "Person")
and exists (select 1 from "Animal" where "Person"."id" = "Animal"."ownerId")
order by "Person"."lastName" asc
Update models:
Person
.query()
.patch({lastName: 'Dinosaur'})
.where('age', '>', 60)
.then(function (numUpdated) {
console.log('all persons over 60 years old are now dinosaurs');
console.log(numUpdated, 'people were updated');.
})
.catch(function (err) {
console.log(err.stack);
});
update "Person" set "lastName" = 'Dinosaur' where "age" > 60
The .patch()
and .update()
method return the number of updated rows. If you want the freshly updated
model as a result you can use the helper method .patchAndFetchById()
and .updateAndFetchById()
.
Person
.query()
.patchAndFetchById(246, {lastName: 'Updated'})
.then(function (updated) {
console.log(updated.lastName);
})
.catch(function (err) {
console.log(err.stack);
});
update "Person" set "lastName" = 'Updated' where "id" = 246
select * from "Person" where "id" = 246
While the static .query()
method can be used to create a query to a whole table .$relatedQuery()
method
can be used to query a single relation. .$relatedQuery()
returns an instance of QueryBuilder
just like the .query()
method.
var jennifer;
Person
.query()
.where('firstName', 'Jennifer')
.first()
.then(function (person) {
jennifer = person;
return jennifer
.$relatedQuery('pets')
.where('species', 'dog')
.orderBy('name');
})
.then(function (jennifersDogs) {
console.log(jennifersDogs[0] instanceof Animal);
console.log(jennifer.pets === jennifersDogs);
console.log('Jennifer has', jennifersDogs.length, 'dogs');
})
.catch(function (err) {
console.log(err.stack);
});
select * from "Person" where "firstName" = 'Jennifer'
select * from "Animal"
where "species" = 'dog'
and "Animal"."ownerId" = 1
order by "name" asc
Insert a related model:
Person
.query()
.where('id', 1)
.first()
.then(function (person) {
return person.$relatedQuery('pets').insert({name: 'Fluffy'});
})
.then(function (fluffy) {
console.log(fluffy.id);
})
.catch(function (err) {
console.log('something went wrong with finding the person OR inserting the pet');
console.log(err.stack);
});
select * from "Person" where "id" = 1
insert into "Animal" ("name", "ownerId") values ('Fluffy', 1)
Eager queries
Okay I said there is no custom DSL but actually we have teeny-tiny one for fetching relations eagerly, as it isn't
something that can be done easily using SQL. In addition to making your life easier, eager queries avoid the select N+1
problem and provide a great performance. The following examples demonstrate how to use it:
Fetch the pets
relation for all results of a query:
Person
.query()
.eager('pets')
.then(function (persons) {
console.log(persons[0].pets[0].name);
console.log(persons[0].pets[0] instanceof Animal);
});
Fetch multiple relations on multiple levels:
Person
.query()
.eager('[pets, children.[pets, children]]')
.then(function (persons) {
console.log(persons[0].pets[0].name);
console.log(persons[1].children[2].pets[1].name);
console.log(persons[1].children[2].children[0].name);
});
Fetch one relation recursively:
Person
.query()
.eager('[pets, children.^]')
.then(function (persons) {
console.log(persons[0].children[0].children[0].children[0].children[0].firstName);
});
Relations can be filtered using named filters like this:
Person
.query()
.eager('[pets(orderByName, onlyDogs), children(orderByAge).[pets, children]]', {
orderByName: function (builder) {
builder.orderBy('name');
},
orderByAge: function (builder) {
builder.orderBy('age')
},
onlyDogs: function (builder) {
builder.where('species', 'dog')
}
})
.then(function (persons) {
console.log(persons[0].children[0].pets[0].name);
console.log(persons[0].children[0].movies[0].id);
});
The expressions can be arbitrarily deep. See the full description here.
Because the eager expressions are strings they can be easily passed for example as a query parameter of an HTTP
request. However, allowing the client to pass expressions like this without any limitations is not very secure.
Therefore the QueryBuilder has the .allowEager
method.
allowEager can be used to limit the allowed eager expression to a certain subset. Like this:
expressApp.get('/persons', function (req, res, next) {
Person
.query()
.allowEager('[pets, children.pets]')
.eager(req.query.eager)
.then(function (persons) { res.send(persons); })
.catch(next);
});
The example above allows req.query.eager
to be one of:
'pets'
'children'
'children.pets'
'[pets, children]'
'[pets, children.pets]'
.
Examples of failing eager expressions are:
'movies'
'children.children'
'[pets, children.children]'
'notEvenAnExistingRelation'
.
In addition to the .eager
method, relations can be fetched using the loadRelated
and $loadRelated
methods of
Model.
Eager inserts
Arbitrary relation trees can be inserted using the insertWithRelated()
method:
Person
.query()
.insertWithRelated({
firstName: 'Sylvester',
lastName: 'Stallone',
children: [{
firstName: 'Sage',
lastName: 'Stallone',
pets: [{
name: 'Fluffy',
species: 'dog'
}]
}]
});
The query above will insert 'Sylvester', 'Sage' and 'Fluffy' into db and create relationships between them as defined
in the relationMappings
of the models. Technically insertWithRelated
builds a dependency graph from the object
tree and inserts the models that don't depend on any other models until the whole tree is inserted.
If you need to refer to the same model in multiple places you can use the special properties #id
and #ref
like this:
Person
.query()
.insertWithRelated([{
firstName: 'Jennifer',
lastName: 'Lawrence',
movies: [{
"#id": 'silverLiningsPlaybook'
name: 'Silver Linings Playbook',
duration: 122
}]
}, {
firstName: 'Bradley',
lastName: 'Cooper',
movies: [{
"#ref": 'silverLiningsPlaybook'
}]
}]);
The query above will insert only one movie (the 'Silver Linings Playbook') but both 'Jennifer' and 'Bradley' will have
the movie related to them through the many-to-many relation movies
. The #id
can be any string. There are no format
or length requirements for them. It is quite easy to create circular dependencies using #id
and #ref
. Luckily
insertWithRelated
detects them and rejects the query with a clear error message.
You can refer to the properties of other models anywhere in the graph using expressions of format #ref{<id>.<property>}
as long as the reference doesn't create a circular dependency. For example:
Person
.query()
.insertWithRelated([{
"#id": 'jenniLaw',
firstName: 'Jennifer',
lastName: 'Lawrence',
pets: [{
name: "I am the dog of #ref{jenniLaw.firstName} whose id is #ref{jenniLaw.id}",
species: 'dog'
}]
}]);
The query above will insert a pet named I am the dog of Jennifer whose id is 523
for Jennifer. If #ref{}
is used
within a string, the references are replaced with the referred values inside the string. If the reference string
contains nothing but the reference, the referred value is copied to it's place preserving its type.
See the allowInsert method if you need to limit
which relations can be inserted using insertWithRelated
method to avoid security issues.
By the way, if you are using Postgres the inserts are done in batches for maximum performance.
Transactions
There are two ways to use transactions in objection.js
- Transaction callback
- Transaction object
Transaction callback
The first way to work with transactions is to perform all operations inside one callback using the
objection.transaction function. The beauty of this
method is that you don't need to pass a transaction object to each query explicitly as long as you start all queries
using the bound model classes that are passed to the transaction callback as arguments.
Transactions are started by calling the objection.transaction
function. Give all the models you want to use in the transaction as parameters to the transaction
function. The model
classes are bound to a newly created transaction and passed to the callback function. Inside this callback, all queries
started through them take part in the same transaction.
The transaction is committed if the returned Promise is resolved successfully. If the returned Promise is rejected
the transaction is rolled back.
objection.transaction(Person, Animal, function (Person, Animal) {
return Person
.query()
.insert({firstName: 'Jennifer', lastName: 'Lawrence'})
.then(function () {
return Animal
.query()
.insert({name: 'Scrappy'});
});
}).then(function (scrappy) {
console.log('Jennifer and Scrappy were successfully inserted');
}).catch(function (err) {
console.log('Something went wrong. Neither Jennifer nor Scrappy were inserted');
});
You only need to give the transaction
function the model classes you use explicitly. All the related model classes
are implicitly bound to the same transaction.
objection.transaction(Person, function (Person) {
return Person
.query()
.insert({firstName: 'Jennifer', lastName: 'Lawrence'})
.then(function (jennifer) {
return jennifer
.$relatedQuery('pets')
.insert({name: 'Scrappy'});
});
}).then(function (scrappy) {
console.log('Jennifer and Scrappy were successfully inserted');
}).catch(function (err) {
console.log('Something went wrong. Neither Jennifer nor Scrappy were inserted');
});
The only way you can mess up with the transactions is if you explicitly start a query using a model class that is not
bound to the transaction:
var Person = require('./models/Person');
var Animal = require('./models/Animal');
objection.transaction(Person, function (Person) {
return Person
.query()
.insert({firstName: 'Jennifer', lastName: 'Lawrence'})
.then(function (jennifer) {
return Animal
.query()
.insert({name: 'Scrappy'});
});
});
Transaction object
The second way to use transactions is to express the transaction as an object and bind model classes to the transaction
when you use them. This way is more convenient when you need to pass the transaction to functions and services.
The transaction object can be created using the objection.transaction.start
method. You need to remember to call either the commit
or rollback
method of the transaction object.
var trx;
objection.transaction.start(Person).then(function (transaction) {
trx = transaction;
return Person
.bindTransaction(trx)
.query()
.insert({firstName: 'Jennifer', lastName: 'Lawrence'});
}).then(function (jennifer) {
return jennifer
.$relatedQuery('pets')
.insert({name: 'Fluffy'});
}).then(function () {
return Movie
.bindTransaction(trx)
.query()
.where('name', 'ilike', '%forrest%');
}).then(function (movies) {
console.log(movies);
return trx.commit();
}).catch(function () {
return trx.rollback();
});
To understand what is happening in the above example you need to know how bindTransaction
method works.
bindTransaction
actually returns an anonymous subclass of the model class you call it for and sets the
transaction's database connection as that class's database connection. This way all queries started through
that anonymous class use the same connection and take part in the same transaction. If we didn't create a
subclass and just set the original model's database connection, all query chains running in parallel would
suddenly jump into the same transaction and things would go terribly wrong.
Now that you have an idea how the bindTransaction
works you should see that the previous example could
also be implemented like this:
var BoundPerson;
var BoundMovie;
objection.transaction.start(Person).then(function (transaction) {
BoundPerson = Person.bindTransaction(transaction);
BoundMovie = Movie.bindTransaction(transaction);
return BoundPerson
.query()
.insert({firstName: 'Jennifer', lastName: 'Lawrence'});
}).then(function (jennifer) {
return jennifer
.$relatedQuery('pets')
.insert({name: 'Fluffy'});
}).then(function () {
return BoundMovie
.query()
.where('name', 'ilike', '%forrest%');
}).then(function (movies) {
console.log(movies);
return BoundPerson.knex().commit();
}).catch(function () {
return BoundPerson.knex().rollback();
});
which is pretty much what the objection.transaction
function does.
Documents
Objection.js makes it easy to store non-flat documents as table rows. All properties of a model that are marked as
objects or arrays in the model's jsonSchema
are automatically converted to JSON strings in the database and
back to objects when read from the database. The database columns for the object properties can be normal
text columns. Postgresql has the json
and jsonb
data types that can be used instead for better performance
and possibility to make queries to the documents.
The address
property of the Person model is defined as an object in the Person.jsonSchema:
Person
.query()
.insert({
firstName: 'Jennifer',
lastName: 'Lawrence',
age: 24,
address: {
street: 'Somestreet 10',
zipCode: '123456',
city: 'Tampere'
}
})
.then(function (jennifer) {
console.log(jennifer.address.city);
return Person.query().where('id', jennifer.id);
})
.then(function (jenniferFromDb) {
console.log(jenniferFromDb.address.city);
})
.catch(function (err) {
console.log('oh noes');
});
Validation
JSON schema validation can be enabled by setting the jsonSchema property
of a model class. The validation is ran each time a Model
instance is created. For example all these will trigger
the validation:
Person.fromJson({firstName: 'jennifer', lastName: 'Lawrence'});
Person.query().insert({firstName: 'jennifer', lastName: 'Lawrence'});
Person.query().update({firstName: 'jennifer', lastName: 'Lawrence'}).where('id', 10);
Person.query().patch({age: 24}).where('age', '<', 24);
You rarely need to call $validate method explicitly, but you
can do it when needed. If validation fails a ValidationError
will be thrown. Since we use Promises, this usually means that a promise will be rejected with an instance of
ValidationError
.
Person.query().insert({firstName: 'jennifer'}).catch(function (err) {
console.log(err instanceof objection.ValidationError);
console.log(err.data);
});
See the recipe book for instructions
if you want to use some other validation library.
Models
Models are created by inheriting from the Model base class.
In objection.js the inheritance is done as transparently as possible. There is no custom Class abstraction making you
wonder what the hell is happening. Just plain old ugly javascript inheritance.
Minimal model
A working model with minimal amount of code:
var Model = require('objection').Model;
function MinimalModel() {
Model.apply(this, arguments);
}
Model.extend(MinimalModel);
MinimalModel.tableName = 'SomeTableName';
module.exports = MinimalModel;
A model with custom methods, json schema validation and relations
This is the model used in the examples:
var Model = require('objection').Model;
function Person() {
Model.apply(this, arguments);
}
Model.extend(Person);
module.exports = Person;
Person.prototype.fullName = function () {
return this.firstName + ' ' + this.lastName;
};
Person.tableName = 'Person';
Person.jsonSchema = {
type: 'object',
required: ['firstName', 'lastName'],
properties: {
id: {type: 'integer'},
parentId: {type: ['integer', 'null']},
firstName: {type: 'string', minLength: 1, maxLength: 255},
lastName: {type: 'string', minLength: 1, maxLength: 255},
age: {type: 'number'},
address: {
type: 'object',
properties: {
street: {type: 'string'},
city: {type: 'string'},
zipCode: {type: 'string'}
}
}
}
};
Person.relationMappings = {
pets: {
relation: Model.OneToManyRelation,
modelClass: __dirname + '/Animal',
join: {
from: 'Person.id',
to: 'Animal.ownerId'
}
},
movies: {
relation: Model.ManyToManyRelation,
modelClass: __dirname + '/Movie',
join: {
from: 'Person.id',
through: {
from: 'Person_Movie.personId',
to: 'Person_Movie.movieId'
},
to: 'Movie.id'
}
},
parent: {
relation: Model.OneToOneRelation,
modelClass: Person,
join: {
from: 'Person.parentId',
to: 'Person.id'
}
},
children: {
relation: Model.OneToManyRelation,
modelClass: Person,
join: {
from: 'Person.id',
to: 'Person.parentId'
}
}
};
Testing
To run the tests, all you need to do is configure the databases and run npm test
. Check out
this file for the
test database configurations. If you don't want to run the tests against all databases you can
just comment out configurations from the testDatabaseConfigs
list.
Changelog
0.3.3
What's new
- fix regression: QueryBuilder.from is broken.
0.3.2
What's new
- Improved relation expression whitespace handling.
0.3.1
What's new
whereJson*
methods can now be used inside functions given to where
methods.- Added multiple missing knex methods to
QueryBuilder
.
0.3.0
What's new
Breaking changes
- QueryBuilder methods
update
, patch
and delete
now return the number of affected rows.
The new methods updateAndFetchById
and patchAndFetchById
may help with the migration modelInstance.$query()
instance method now returns a single model instead of an array- Removed
Model.generateId()
method. $beforeInsert
can be used instead
0.2.8
What's new
- ES6 inheritance support
- generator function support for transactions
- traverse,pick and omit methods for Model and QueryBuilder
- bugfix: issue #38
0.2.7
What's new
- bugfix: fix #37 also for
$query()
. - Significant
toJson
/fromJson
performance boost.
0.2.6
What's new
- bugfix: fix regression bug that broke dumpSql.
0.2.5
What's new
- bugfix: fix regression bug that prevented values assigned to
this
in $before
callbacks from getting into
the actual database query
0.2.4
What's new
- bugfix: many-to-many relations didn't work correctly with a snake_case to camelCase conversion
in the related model class.
0.2.3
What's new
- Promise constructor is now exposed through
require('objection').Promise
.
0.2.2
What's new
- $beforeUpdate, $afterUpdate, $beforeInsert etc. are now asynchronous and you can return promises from them.
- Added
Model.fn()
shortcut to knex.fn
. - Added missing
asCallback
and nodeify
methods for QueryBuilder
.
0.2.1
What's new
- bugfix: Chaining
insert
with returning
now returns all listed columns.
0.2.0
What's new
- New name
objection.js
. $beforeInsert
, $afterInsert
, $beforeUpdate
and $afterUpdate
hooks for Model
.- Postgres jsonb query methods:
whereJsonEquals
, whereJsonSupersetOf
, whereJsonSubsetOf
and friends. whereRef
query method.- Expose
knex.raw()
through Model.raw()
. - Expose
knex.client.formatter()
through Model.formatter()
. QueryBuilder
can be used to make sub queries just like knex's QueryBuilder
.- Possibility to use a custom
QueryBuilder
subclass by overriding Model.QueryBuilder
. - Filter queries/objects for relations.
- A pile of bug fixes.
Breaking changes
- Project was renamed to objection.js. Migrate simply by replacing
moron
with objection
.
0.1.0
First release.