Object Relational Mapping
Install
npm install orm
Node.js Version Support
Tests are done using Travis CI for node versions 0.6.x
, 0.8.x
and 0.10.x
. If you want you can run
tests locally.
npm test
DBMS Support
- MySQL
- PostgreSQL
- Amazon Redshift
- SQLite
- MongoDB (beta, missing aggregation for now)
Features
- Create Models, sync, drop, bulk create, get, find, remove, count, aggregated functions
- Create Model associations, find, check, create and remove
- Define custom validations (several builtin validations, check instance properties before saving - see enforce for details)
- Model instance caching and integrity (table rows fetched twice are the same object, changes to one change all)
- Plugins: MySQL FTS , Pagination , Transaction, Timestamps
Introduction
This is a node.js object relational mapping module.
An example:
var orm = require("orm");
orm.connect("mysql://username:password@host/database", function (err, db) {
if (err) throw err;
var Person = db.define("person", {
name : String,
surname : String,
age : Number,
male : Boolean,
continent : [ "Europe", "America", "Asia", "Africa", "Australia", "Antartica" ],
photo : Buffer,
data : Object
}, {
methods: {
fullName: function () {
return this.name + ' ' + this.surname;
}
},
validations: {
age: orm.enforce.ranges.number(18, undefined, "under-age")
}
});
Person.find({ surname: "Doe" }, function (err, people) {
console.log("People found: %d", people.length);
console.log("First person: %s, age %d", people[0].fullName(), people[0].age);
people[0].age = 16;
people[0].save(function (err) {
});
});
});
Express
If you're using Express, you might want to use the simple middleware to integrate more easily.
var express = require('express');
var orm = require('orm');
var app = express();
app.use(orm.express("mysql://username:password@host/database", {
define: function (db, models, next) {
models.person = db.define("person", { ... });
next();
}
}));
app.listen(80);
app.get("/", function (req, res) {
req.models.person.find(...);
});
You can call orm.express
more than once to have multiple database connections. Models defined across connections
will be joined together in req.models
. Don't forget to use it before app.use(app.router)
, preferably right after your
assets public folder(s).
Documentation
Documentation is moving to the wiki.
Settings
See information in the wiki.
Connecting
See information in the wiki.
Models
A Model is an abstraction over one or more database tables. Models support associations (more below). The name of the model is assumed to match the table name.
Models support behaviours for accessing and manipulating table data.
Defining Models
See information in the wiki.
Properties
See information in the wiki.
Instance Methods
Are passed in during model definition.
var Person = db.define('person', {
name : String,
surname : String
}, {
methods: {
fullName: function () {
return this.name + ' ' + this.surname;
}
}
});
Person.get(4, function(err, person) {
console.log( person.fullName() );
})
Model Methods
Are defined directly on the model.
var Person = db.define('person', {
name : String,
height : { type: 'number', rational: false }
});
Person.tallerThan = function(height, callback) {
this.find({ height: orm.gt(height) }, callback);
};
Person.tallerThan( 192, function(err, tallPeople) { ... } );
Loading Models
Models can be in separate modules. Simply ensure that the module holding the models uses module.exports to publish a function that accepts the database connection, then load your models however you like.
Note - using this technique you can have cascading loads.
db.load("./models", function (err) {
var Person = db.models.person;
var Pet = db.models.pet;
});
module.exports = function (db, cb) {
db.load("./models-extra", function (err) {
if (err) {
return cb(err);
}
db.define('person', {
name : String
});
return cb();
});
};
module.exports = function (db, cb) {
db.define('pet', {
name : String
});
return cb();
};
Synchronizing Models
See information in the wiki.
Dropping Models
See information in the wiki.
Advanced Options
ORM2 allows you some advanced tweaks on your Model definitions. You can configure these via settings or in the call to define
when you setup the Model.
For example, each Model instance has a unique ID in the database. This table column is
by default "id" but you can change it.
var Person = db.define("person", {
name : String
}, {
id : "person_id"
});
db.settings.set("properties.primary_key", "UID");
var Pet = db.define("pet", {
name : String
});
Pet model will have 2 columns, an UID
and a name
.
It is also possible to have multiple IDs for a model in the database, this is done by specifying an array of IDs to use.
var Person = db.define("person", {
firstname: String,
lastname: String
}, {
id: ['firstname', 'lastname']
});
Other options:
cache
: (default: true
) Set it to false
to disable Instance cache (Singletons) or set a timeout value (in seconds);autoSave
: (default: false
) Set it to true
to save an Instance right after changing any property;autoFetch
: (default: false
) Set it to true
to fetch associations when fetching an instance from the database;autoFetchLimit
: (default: 1
) If autoFetch
is enabled this defines how many hoops (associations of associations)
you want it to automatically fetch.
Hooks
See information in the wiki.
Finding Items
Model.get(id, [ options ], cb)
To get a specific element from the database use Model.get
.
Person.get(123, function (err, person) {
});
Model.find([ conditions ] [, options ] [, limit ] [, order ] [, cb ])
Finding one or more elements has more options, each one can be given in no specific parameter order. Only options
has to be after conditions
(even if it's an empty object).
Person.find({ name: "John", surname: "Doe" }, 3, function (err, people) {
});
If you need to sort the results because you're limiting or just because you want them sorted do:
Person.find({ surname: "Doe" }, "name", function (err, people) {
});
Person.find({ surname: "Doe" }, [ "name", "Z" ], function (err, people) {
});
There are more options that you can pass to find something. These options are passed in a second object:
Person.find({ surname: "Doe" }, { offset: 2 }, function (err, people) {
});
You can also use raw SQL when searching. It's documented in the Chaining section below.
Model.count([ conditions, ] cb)
If you just want to count the number of items that match a condition you can just use .count()
instead of finding all
of them and counting. This will actually tell the database server to do a count (it won't be done in the node process itself).
Person.count({ surname: "Doe" }, function (err, count) {
console.log("We have %d Does in our db", count);
});
Model.exists([ conditions, ] cb)
Similar to .count()
, this method just checks if the count is greater than zero or not.
Person.exists({ surname: "Doe" }, function (err, exists) {
console.log("We %s Does in our db", exists ? "have" : "don't have");
});
Aggregating Functions
If you need to get some aggregated values from a Model, you can use Model.aggregate()
. Here's an example to better
illustrate:
Person.aggregate({ surname: "Doe" }).min("age").max("age").get(function (err, min, max) {
console.log("The youngest Doe guy has %d years, while the oldest is %d", min, max);
});
An Array
of properties can be passed to select only a few properties. An Object
is also accepted to define conditions.
Here's an example to illustrate how to use .groupBy()
:
Person.aggregate(["age"], { country: "someCountry" }).avg("weight").groupBy("age").get(function (err, stats) {
});
Base .aggregate()
methods
.limit()
: you can pass a number as a limit, or two numbers as offset and limit respectively.order()
: same as Model.find().order()
Additional .aggregate()
methods
min
max
avg
sum
count
(there's a shortcut to this - Model.count
)
There are more aggregate functions depending on the driver (Math functions for example).
Chaining
If you prefer less complicated syntax you can chain .find()
by not giving a callback parameter.
Person.find({ surname: "Doe" }).limit(3).offset(2).only("name", "surname").run(function (err, people) {
});
Chaining allows for more complicated queries. For example, we can search by specifying custom SQL:
Person.find({ age: 18 }).where("LOWER(surname) LIKE ?", ['dea%']).all( ... );
It's bad practice to manually escape SQL parameters as it's error prone and exposes your application to SQL injection.
The ?
syntax takes care of escaping for you, by safely substituting the question mark in the query with the parameters provided.
You can also chain multiple where
clauses as needed.
You can also order
or orderRaw
:
Person.find({ age: 18 }).order('-name').all( ... );
Person.find({ age: 18 }).orderRaw("?? DESC", ['age']).all( ... );
You can also chain and just get the count in the end. In this case, offset, limit and order are ignored.
Person.find({ surname: "Doe" }).count(function (err, people) {
});
Also available is the option to remove the selected items.
Person.find({ surname: "Doe" }).remove(function (err) {
});
You can also make modifications to your instances using common Array traversal methods and save everything
in the end.
Person.find({ surname: "Doe" }).each(function (person) {
person.surname = "Dean";
}).save(function (err) {
});
Person.find({ surname: "Doe" }).each().filter(function (person) {
return person.age >= 18;
}).sort(function (person1, person2) {
return person1.age < person2.age;
}).get(function (people) {
});
Of course you could do this directly on .find()
, but for some more complicated tasks this can be very usefull.
Model.find()
does not return an Array so you can't just chain directly. To start chaining you have to call
.each()
(with an optional callback if you want to traverse the list). You can then use the common functions
.filter()
, .sort()
and .forEach()
more than once.
In the end (or during the process..) you can call:
.count()
if you just want to know how many items there are;.get()
to retrieve the list;.save()
to save all item changes.
Conditions
Conditions are defined as an object where every key is a property (table column). All keys are supposed
to be concatenated by the logical AND
. Values are considered to match exactly, unless you're passing
an Array
. In this case it is considered a list to compare the property with.
{ col1: 123, col2: "foo" }
{ col1: [ 1, 3, 5 ] }
If you need other comparisons, you have to use a special object created by some helper functions. Here are
a few examples to describe it:
{ col1: orm.eq(123) }
{ col1: orm.ne(123) }
{ col1: orm.gt(123) }
{ col1: orm.gte(123) }
{ col1: orm.lt(123) }
{ col1: orm.lte(123) }
{ col1: orm.between(123, 456) }
{ col1: orm.not_between(123, 456) }
{ col1: orm.like(12 + "%") }
Raw queries
db.driver.execQuery("SELECT id, email FROM user", function (err, data) { ... })
db.driver.execQuery(
"SELECT user.??, user.?? FROM user WHERE user.?? LIKE ? AND user.?? > ?",
['id', 'name', 'name', 'john', 'id', 55],
function (err, data) { ... }
)
db.driver.execQuery(
"SELECT user.id, user.name FROM user WHERE user.name LIKE ? AND user.id > ?",
['john', 55],
function (err, data) { ... }
)
Caching & Integrity
Model instances are cached. If multiple different queries will result in the same result, you will
get the same object. If you have other systems that can change your database (or you're developing and need
to make some manual changes) you should remove this feature by disabling cache. This can be done when you're
defining the Model.
var Person = db.define('person', {
name : String
}, {
cache : false
});
and also globally:
orm.connect('...', function(err, db) {
db.settings.set('instance.cache', false);
});
The cache can be configured to expire after a period of time by passing in a number instead of a
boolean. The number will be considered the cache timeout in seconds (you can use floating point).
Note: One exception about Caching is that it won't be used if an instance is not saved. For example, if
you fetch a Person and then change it, while it doesn't get saved it won't be passed from Cache.
Creating Items
Model.create(items, cb)
To insert new elements to the database use Model.create
.
Person.create([
{
name: "John",
surname: "Doe",
age: 25,
male: true
},
{
name: "Liza",
surname: "Kollan",
age: 19,
male: false
}
], function (err, items) {
});
Updating Items
Every item returned has the properties that were defined to the Model and also a couple of methods you can
use to change each item.
Person.get(1, function (err, John) {
John.name = "Joe";
John.surname = "Doe";
John.save(function (err) {
console.log("saved!");
});
});
Updating and then saving an instance can be done in a single call:
Person.get(1, function (err, John) {
John.save({ name: "Joe", surname: "Doe" }, function (err) {
console.log("saved!");
});
});
If you want to remove an instance, just do:
Person.get(1, function (err, John) {
John.remove(function (err) {
console.log("removed!");
});
});
Validations
See information in the wiki.
Associations
An association is a relation between one or more tables.
hasOne
Is a many to one relationship. It's the same as belongs to.
Eg: Animal.hasOne('owner', Person)
.
Animal can only have one owner, but Person can have many animals.
Animal will have the owner_id
property automatically added.
The following functions will become available:
animal.getOwner(function..)
animal.setOwner(person, function..)
animal.hasOwner(function..)
animal.removeOwner()
Reverse access
Animal.hasOne('owner', Person, {reverse: 'pets'})
will add the following:
person.getPets(function..)
person.setPets(cat, function..)
hasMany
Is a many to many relationship (includes join table).
Eg: Patient.hasMany('doctors', Doctor, { why: String }, { reverse: 'patients' })
.
Patient can have many different doctors. Each doctor can have many different patients.
This will create a join table patient_doctors
when you call Patient.sync()
:
column name | type |
---|
patient_id | Integer |
doctor_id | Integer |
why | varchar(255) |
The following functions will be available:
patient.getDoctors(function..)
patient.addDoctors(docs, function...)
patient.setDoctors(docs, function...)
patient.hasDoctors(docs, function...)
patient.removeDoctors(docs, function...)
doctor.getPatients(function..)
etc...
To associate a doctor to a patient:
patient.addDoctor(surgeon, {why: "remove appendix"}, function(err) { ... } )
which will add {patient_id: 4, doctor_id: 6, why: "remove appendix"}
to the join table.
getAccessor
This accessor in this type of association returns a ChainFind
if not passing a callback. This means you can
do things like:
patient.getDoctors().order("name").offset(1).run(function (err, doctors), {
});
extendsTo
If you want to split maybe optional properties into different tables or collections. Every extension will be in a new table,
where the unique identifier of each row is the main model instance id. For example:
var Person = db.define("person", {
name : String
});
var PersonAddress = Person.extendsTo("address", {
street : String,
number : Number
});
This will create a table person
with columns id
and name
. The extension will create a table person_address
with
columns person_id
, street
and number
. The methods available in the Person
model are similar to an hasOne
association. In this example you would be able to call .getAddress(cb)
, .setAddress(Address, cb)
, ..
Note: you don't have to save the result from Person.extendsTo
. It returns an extended model. You can use it to query
directly this extended table (and even find the related model) but that's up to you. If you only want to access it using the
original model you can just discard the return.
Examples & options
If you have a relation of 1 to n, you should use hasOne
(belongs to) association.
var Person = db.define('person', {
name : String
});
var Animal = db.define('animal', {
name : String
});
Animal.hasOne("owner", Person);
Animal.get(123, function (err, animal) {
animal.getOwner(function (err, person) {
});
});
You can mark the owner_id
field as required in the database by specifying the required
option:
Animal.hasOne("owner", Person, { required: true });
If you prefer to use another name for the field (owner_id) you can change this parameter in the settings.
db.settings.set("properties.association_key", "{field}_{name}");
Note: This has to be done before the association is specified.
The hasMany
associations can have additional properties in the association table.
var Person = db.define('person', {
name : String
});
Person.hasMany("friends", {
rate : Number
});
Person.get(123, function (err, John) {
John.getFriends(function (err, friends) {
});
});
If you prefer you can activate autoFetch
.
This way associations are automatically fetched when you get or find instances of a model.
var Person = db.define('person', {
name : String
});
Person.hasMany("friends", {
rate : Number
}, {
autoFetch : true
});
Person.get(123, function (err, John) {
});
You can also define this option globally instead of a per association basis.
var Person = db.define('person', {
name : String
}, {
autoFetch : true
});
Person.hasMany("friends", {
rate : Number
});
Associations can make calls to the associated Model by using the reverse
option. For example, if you have an
association from ModelA to ModelB, you can create an accessor in ModelB to get instances from ModelA.
Confusing? Look at the next example.
var Pet = db.define('pet', {
name : String
});
var Person = db.define('person', {
name : String
});
Pet.hasOne("owner", Person, {
reverse : "pets"
});
Person(4).getPets(function (err, pets) {
});
This makes even more sense when having hasMany
associations since you can manage the many to many
associations from both sides.
var Pet = db.define('pet', {
name : String
});
var Person = db.define('person', {
name : String
});
Person.hasMany("pets", Pet, {
bought : Date
}, {
reverse : "owners"
});
Person(1).getPets(...);
Pet(2).getOwners(...);