Object Relational Mapping
Install
npm install orm
DBMS Support
- MySQL
- PostgreSQL
- Amazon Redshift
- SQLite
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)
- Model instance caching and integrity (table rows fetched twice are the same object, changes to one change all)
- Plugins: MySQL FTS , Pagination
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.validators.rangeNumber(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) {
models.person = db.define("person", { ... });
}
}));
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).
Settings
Settings are used to store key value pairs. A settings object is stored on the global orm object and on each database connection.
var orm = require("orm");
orm.settings.set("some.deep.value", 123);
orm.connect("....", function (err, db) {
console.log(db.settings.get("some.deep.value"));
console.log(db.settings.get("some.deep"));
});
Connecting
First, add the correct driver to your package.json
:
driver | dependency |
---|
mysql | "mysql" : "2.0.0-alpha7" |
postgres redshift | "pg": "~1.0.0" |
sqlite | "sqlite3" : "2.1.7" |
Options
You can pass in connection options either as a string:
var orm = require("orm");
orm.connect("mysql://username:password@host/database?pool=true", function (err, db) {
});
Note: pool
is only supported by mysql & postgres.
Or as an object:
var opts = {
database : "dbname",
protocol : "[mysql|postgres|redshift|sqlite]",
host : "127.0.0.1",
port : 3306,
user : "..",
password : "..",
query : {
pool : true|false,
debug : true|false
}
};
orm.connect(opts, function (err, db) {
});
You can also avoid passing a callback and just listen for the connect event:
var orm = require("orm");
var db = orm.connect("mysql://username:password@host/database");
db.on("connect", function (err, db) {
});
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
Call define
on the database connection to setup a model. The name of the table and model is used as an identifier for the model on the database connection, so you can easily access the model later using the connection.
var Person = db.define('person', {
name : String,
surname : { type: "text", size: 50 }
}, {
});
Properties
Types
Native | String | Native | String |
---|
String | 'text' | Date | 'date ' |
Number | 'number' | Object | 'object' |
Boolean | 'boolean' | Buffer | 'binary' |
| | --- | 'enum'
Options
[all types]
required
: true marks the column as NOT NULL
, false (default)defaultValue
: sets the default value for the field
string
size
: max length of the string
number
rational
: true (default) creates a FLOAT/REAL, false an INTEGERsize
: byte size of number, default is 4. Note that 8 byte numbers have limitationsunsigned
: true to make INTEGER unsigned, default is false
date
time
: true (default) creates a DATETIME/TIMESTAMP, false a DATE
Note that these may vary accross drivers.
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
Models can create their underlying tables in the database. You may call Model.sync() on each Model to create the underlying table or you can call db.sync() at a connection level to create all tables for all models.
Person.sync(function (err) {
!err && console.log("done!");
});
Dropping Models
If you want to drop a Model and remove all tables you can use the .drop()
method.
Person.drop(function (err) {
!err && console.log("person model no longer exists!");
});
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
.
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
If you want to listen for a type of event than occurs in instances of a Model, you can attach a function that
will be called when that event happens.
Currently the following events are supported:
afterLoad
: (no parameters) Right after loading and preparing an instance to be used;beforeSave
: (no parameters) Right before trying to save;afterSave
: (bool success) Right after saving;beforeCreate
: (no parameters) Right before trying to save a new instance (prior to beforeSave
);afterCreate
: (bool success) Right after saving a new instance;beforeRemove
: (no parameters) Right before trying to remove an instance;afterRemove
: (bool success) Right after removing an instance;beforeValidation
: (no parameters) Before all validations and prior to beforeCreate
and beforeSave
;
All hook function are called with this
as the instance so you can access anything you want related to it.
For all before*
hooks, you can add an additional parameter to the hook function. This parameter will be a function that
must be called to tell if the hook allows the execution to continue or to break. You might be familiar with this workflow
already from Express. Here's an example:
var Person = db.define("person", {
name : String,
surname : String
}, {
hooks: {
beforeCreate: function (next) {
if (this.surname == "Doe") {
return next(new Error("No Does allowed"));
}
return next();
}
}
});
This workflow allows you to make asynchronous work before calling next
.
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) {
});
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) {
});
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.like(12 + "%") }
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
You can define validations for every property of a Model. You can have one or more validations for each property.
You can also use the predefined validations or create your own.
var Person = db.define("person", {
name : String,
age : Number
}, {
validations : {
name : orm.validators.rangeLength(1, undefined, "missing"),
age : [ orm.validators.rangeNumber(0, 10), orm.validators.insideList([ 1, 3, 5, 7, 9 ]) ]
}
});
The code above defines that the name
length must be between 1 and undefined (undefined means any) and age
must be a number between 0 and 10 (inclusive) but also one of the listed values. The example might not make sense
but you get the point.
When saving an item, if it fails to validate any of the defined validations you'll get an error
object with the property
name and validation error description. This description should help you identify what happened.
var John = new Person({
name : "",
age : 20
});
John.save(function (err) {
});
The validation stops after the first validation error. If you want it to validate every property and return all validation
errors, you can change this behavior on global or local settings:
var orm = require("orm");
orm.settings.set("instance.returnAllErrors", true);
orm.connect("....", function (err, db) {
db.settings.set("instance.returnAllErrors", true);
var John = new Person({
name : "",
age : 15
});
John.save(function (err) {
assert(Array.isArray(err));
});
});
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.
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) {
Foo.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", "id_{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(...);