Embedded persistent database for Node.js, written in Javascript, with no dependency (except npm
modules of course). You can think of it as a SQLite for Node.js projects, which
can be used with a simple require
statement. The API is a subset of MongoDB's. You can use it as a persistent or an in-memory only datastore.
NeDB is not intended to be a replacement of large-scale databases such as MongoDB! Its goal is to provide you with a clean and easy way to query data and persist it to disk, for web applications that do not need lots of concurrent connections, for example a continuous integration and deployment server and desktop applications built with Node Webkit.
NeDB was benchmarked against the popular client-side database TaffyDB and NeDB is much, much faster. That's why there is now a browser version, which can also provide persistence.
Check the change log in the wiki if you think nedb doesn't behave as the documentation describes! Most of the issues I get are due to non-latest version NeDBs.
No time to help out? You can support NeDB development by sending money or bitcoins!
Bitcoin address: 1dDZLnWpBbodPiN8sizzYrgaz5iahFyb1
Module name on npm is nedb
.
npm install nedb --save // Put latest version in your package.json
npm test // You'll need the dev dependencies to test it
It's a subset of MongoDB's API (the most used operations). The current API will not change, but I will add operations as they are needed. Summary of the API:
- Creating/loading a database
- Compacting the database
- Inserting documents
- Finding documents
- Counting documents
- Updating documents
- Removing documents
- Indexing
- Browser version
You can use NeDB as an in-memory only datastore or as a persistent datastore. One datastore is the equivalent of a MongoDB collection. The constructor is used as follows new Datastore(options)
where options
is an object with the following fields:
filename
(optional): path to the file where the data is persisted. If left blank, the datastore is automatically considered in-memory only. It cannot end with a~
which is used in the temporary files NeDB uses to perform crash-safe writesinMemoryOnly
(optional, defaults to false): as the name implies.autoload
(optional, defaults to false): if used, the database will automatically be loaded from the datafile upon creation (you don't need to callloadDatabase
). Any command issued before load is finished is buffered and will be executed when load is done.onload
(optional): if you use autoloading, this is the handler called after theloadDatabase
. It takes oneerror
argument. If you use autoloading without specifying this handler, and an error happens during load, an error will be thrown.afterSerialization
(optional): hook you can use to transform data after it was serialized and before it is written to disk. Can be used for example to encrypt data before writing database to disk. This function takes a string as parameter (one line of an NeDB data file) and outputs the transformed string, which must absolutely not contain a\n
character (or data will be lost)beforeDeserialization
(optional): reverse ofafterSerialization
. Make sure to include both and not just one or you risk data loss. For the same reason, make sure both functions are inverses of one another. Some failsafe mechanisms are in place to prevent data loss if you misuse the serialization hooks: NeDB checks that never one is declared without the other, and checks that they are reverse of one another by testing on random strings of various lengths. In addition, if too much data is detected as corrupt, NeDB will refuse to start as it could mean you're not using the deserialization hook corresponding to the serialization hook used before (see below)corruptAlertThreshold
(optional): between 0 and 1, defaults to 10%. NeDB will refuse to start if more than this percentage of the datafile is corrupt. 0 means you don't tolerate any corruption, 1 means you don't carenodeWebkitAppName
(optional, DEPRECATED): if you are using NeDB from whithin a Node Webkit app, specify its name (the same one you use in thepackage.json
) in this field and thefilename
will be relative to the directory Node Webkit uses to store the rest of the application's data (local storage etc.). It works on Linux, OS X and Windows. Now that you can userequire('nw.gui').App.dataPath
in Node Webkit to get the path to the data directory for your application, you should not use this option anymore and it will be removed.
If you use a persistent datastore without the autoload
option, you need to call loadDatabase
manually.
This function fetches the data from datafile and prepares the database. Don't forget it! If you use a
persistent datastore, no command (insert, find, update, remove) will be executed before loadDatabase
is called, so make sure to call it yourself or use the autoload
option.
// Type 1: In-memory only datastore (no need to load the database)
var Datastore = require('nedb')
, db = new Datastore();
// Type 2: Persistent datastore with manual loading
var Datastore = require('nedb')
, db = new Datastore({ filename: 'path/to/datafile' });
db.loadDatabase(function (err) { // Callback is optional
// Now commands will be executed
});
// Type 3: Persistent datastore with automatic loading
var Datastore = require('nedb')
, db = new Datastore({ filename: 'path/to/datafile', autoload: true });
// You can issue commands right away
// Type 4: Persistent datastore for a Node Webkit app called 'nwtest'
// For example on Linux, the datafile will be ~/.config/nwtest/nedb-data/something.db
var Datastore = require('nedb')
, path = require('path')
, db = new Datastore({ filename: path.join(require('nw.gui').App.dataPath, 'something.db') });
// Of course you can create multiple datastores if you need several
// collections. In this case it's usually a good idea to use autoload for all collections.
db = {};
db.users = new Datastore('path/to/users.db');
db.robots = new Datastore('path/to/robots.db');
// You need to load each database (here we do it asynchronously)
db.users.loadDatabase();
db.robots.loadDatabase();
Under the hood, NeDB's persistence uses an append-only format, meaning that all updates and deletes actually result in lines added at the end of the datafile. The reason for this is that disk space is very cheap and appends are much faster than rewrites since they don't do a seek. The database is automatically compacted (i.e. put back in the one-line-per-document format) everytime your application restarts.
You can manually call the compaction function with yourDatabase.persistence.compactDatafile
which takes no argument. It queues a compaction of the datafile in the executor, to be executed sequentially after all pending operations.
You can also set automatic compaction at regular intervals with yourDatabase.persistence.setAutocompactionInterval(interval)
, interval
in milliseconds (a minimum of 5s is enforced), and stop automatic compaction with yourDatabase.persistence.stopAutocompaction()
.
Keep in mind that compaction takes a bit of time (not too much: 130ms for 50k records on my slow machine) and no other operation can happen when it does, so most projects actually don't need to use it.
The native types are String
, Number
, Boolean
, Date
and null
. You can also use
arrays and subdocuments (objects). If a field is undefined
, it will not be saved (this is different from
MongoDB which transforms undefined
in null
, something I find counter-intuitive).
If the document does not contain an _id
field, NeDB will automatically generated one for you (a 16-characters alphanumerical string). The _id
of a document, once set, cannot be modified.
Field names cannot begin by '$' or contain a '.'.
var doc = { hello: 'world'
, n: 5
, today: new Date()
, nedbIsAwesome: true
, notthere: null
, notToBeSaved: undefined // Will not be saved
, fruits: [ 'apple', 'orange', 'pear' ]
, infos: { name: 'nedb' }
};
db.insert(doc, function (err, newDoc) { // Callback is optional
// newDoc is the newly inserted document, including its _id
// newDoc has no key called notToBeSaved since its value was undefined
});
You can also bulk-insert an array of documents. This operation is atomic, meaning that if one insert fails due to a unique constraint being violated, all changes are rolled back.
db.insert([{ a: 5 }, { a: 42 }], function (err, newDocs) {
// Two documents were inserted in the database
// newDocs is an array with these documents, augmented with their _id
});
// If there is a unique constraint on field 'a', this will fail
db.insert([{ a: 5 }, { a: 42 }, { a: 5 }], function (err) {
// err is a 'uniqueViolated' error
// The database was not modified
});
Use find
to look for multiple documents matching you query, or findOne
to look for one specific document. You can select documents based on field equality or use comparison operators ($lt
, $lte
, $gt
, $gte
, $in
, $nin
, $ne
). You can also use logical operators $or
, $and
, $not
and $where
. See below for the syntax.
You can use regular expressions in two ways: in basic querying in place of a string, or with the $regex
operator.
You can sort and paginate results using the cursor API (see below).
You can use standard projections to restrict the fields to appear in the results (see below).
Basic querying means are looking for documents whose fields match the ones you specify. You can use regular expression to match strings. You can use the dot notation to navigate inside nested documents, arrays, arrays of subdocuments and to match a specific element of an array.
// Let's say our datastore contains the following collection
// { _id: 'id1', planet: 'Mars', system: 'solar', inhabited: false, satellites: ['Phobos', 'Deimos'] }
// { _id: 'id2', planet: 'Earth', system: 'solar', inhabited: true, humans: { genders: 2, eyes: true } }
// { _id: 'id3', planet: 'Jupiter', system: 'solar', inhabited: false }
// { _id: 'id4', planet: 'Omicron Persei 8', system: 'futurama', inhabited: true, humans: { genders: 7 } }
// { _id: 'id5', completeData: { planets: [ { name: 'Earth', number: 3 }, { name: 'Mars', number: 2 }, { name: 'Pluton', number: 9 } ] } }
// Finding all planets in the solar system
db.find({ system: 'solar' }, function (err, docs) {
// docs is an array containing documents Mars, Earth, Jupiter
// If no document is found, docs is equal to []
});
// Finding all planets whose name contain the substring 'ar' using a regular expression
db.find({ planet: /ar/ }, function (err, docs) {
// docs contains Mars and Earth
});
// Finding all inhabited planets in the solar system
db.find({ system: 'solar', inhabited: true }, function (err, docs) {
// docs is an array containing document Earth only
});
// Use the dot-notation to match fields in subdocuments
db.find({ "humans.genders": 2 }, function (err, docs) {
// docs contains Earth
});
// Use the dot-notation to navigate arrays of subdocuments
db.find({ "completeData.planets.name": "Mars" }, function (err, docs) {
// docs contains document 5
});
db.find({ "completeData.planets.name": "Jupiter" }, function (err, docs) {
// docs is empty
});
db.find({ "completeData.planets.0.name": "Earth" }, function (err, docs) {
// docs contains document 5
// If we had tested against "Mars" docs would be empty because we are matching against a specific array element
});
// You can also deep-compare objects. Don't confuse this with dot-notation!
db.find({ humans: { genders: 2 } }, function (err, docs) {
// docs is empty, because { genders: 2 } is not equal to { genders: 2, eyes: true }
});
// Find all documents in the collection
db.find({}, function (err, docs) {
});
// The same rules apply when you want to only find one document
db.findOne({ _id: 'id1' }, function (err, doc) {
// doc is the document Mars
// If no document is found, doc is null
});
The syntax is { field: { $op: value } }
where $op
is any comparison operator:
$lt
,$lte
: less than, less than or equal$gt
,$gte
: greater than, greater than or equal$in
: member of.value
must be an array of values$ne
,$nin
: not equal, not a member of$exists
: checks whether the document posses the propertyfield
.value
should be true or false$regex
: checks whether a string is matched by the regular expression. Contrary to MongoDB, the use of$options
with$regex
is not supported, because it doesn't give you more power than regex flags. Basic queries are more readable so only use the$regex
operator when you need to use another operator with it (see example below)
// $lt, $lte, $gt and $gte work on numbers and strings
db.find({ "humans.genders": { $gt: 5 } }, function (err, docs) {
// docs contains Omicron Persei 8, whose humans have more than 5 genders (7).
});
// When used with strings, lexicographical order is used
db.find({ planet: { $gt: 'Mercury' }}, function (err, docs) {
// docs contains Omicron Persei 8
})
// Using $in. $nin is used in the same way
db.find({ planet: { $in: ['Earth', 'Jupiter'] }}, function (err, docs) {
// docs contains Earth and Jupiter
});
// Using $exists
db.find({ satellites: { $exists: true } }, function (err, docs) {
// docs contains only Mars
});
// Using $regex with another operator
db.find({ planet: { $regex: /ar/, $nin: ['Jupiter', 'Earth'] } }, function (err, docs) {
// docs only contains Mars because Earth was excluded from the match by $nin
});
When a field in a document is an array, NeDB first tries to see if there is an array-specific comparison function (for now there is only $size
) being used
and tries it first. If there isn't, the query is treated as a query on every element and there is a match if at least one element matches.
// Using an array-specific comparison function
// Note: you can't use nested comparison functions, e.g. { $size: { $lt: 5 } } will throw an error
db.find({ satellites: { $size: 2 } }, function (err, docs) {
// docs contains Mars
});
db.find({ satellites: { $size: 1 } }, function (err, docs) {
// docs is empty
});
// If a document's field is an array, matching it means matching any element of the array
db.find({ satellites: 'Phobos' }, function (err, docs) {
// docs contains Mars. Result would have been the same if query had been { satellites: 'Deimos' }
});
// This also works for queries that use comparison operators
db.find({ satellites: { $lt: 'Amos' } }, function (err, docs) {
// docs is empty since Phobos and Deimos are after Amos in lexicographical order
});
// This also works with the $in and $nin operator
db.find({ satellites: { $in: ['Moon', 'Deimos'] } }, function (err, docs) {
// docs contains Mars (the Earth document is not complete!)
});
You can combine queries using logical operators:
- For
$or
and$and
, the syntax is{ $op: [query1, query2, ...] }
. - For
$not
, the syntax is{ $not: query }
- For
$where
, the syntax is{ $where: function () { /* object is "this", return a boolean */ } }
db.find({ $or: [{ planet: 'Earth' }, { planet: 'Mars' }] }, function (err, docs) {
// docs contains Earth and Mars
});
db.find({ $not: { planet: 'Earth' } }, function (err, docs) {
// docs contains Mars, Jupiter, Omicron Persei 8
});
db.find({ $where: function () { return Object.keys(this) > 6; } }, function (err, docs) {
// docs with more than 6 properties
});
// You can mix normal queries, comparison queries and logical operators
db.find({ $or: [{ planet: 'Earth' }, { planet: 'Mars' }], inhabited: true }, function (err, docs) {
// docs contains Earth
});
If you don't specify a callback to find
, findOne
or count
, a Cursor
object is returned. You can modify the cursor with sort
, skip
and limit
and then execute it with exec(callback)
.
// Let's say the database contains these 4 documents
// doc1 = { _id: 'id1', planet: 'Mars', system: 'solar', inhabited: false, satellites: ['Phobos', 'Deimos'] }
// doc2 = { _id: 'id2', planet: 'Earth', system: 'solar', inhabited: true, humans: { genders: 2, eyes: true } }
// doc3 = { _id: 'id3', planet: 'Jupiter', system: 'solar', inhabited: false }
// doc4 = { _id: 'id4', planet: 'Omicron Persei 8', system: 'futurama', inhabited: true, humans: { genders: 7 } }
// No query used means all results are returned (before the Cursor modifiers)
db.find({}).sort({ planet: 1 }).skip(1).limit(2).exec(function (err, docs) {
// docs is [doc3, doc1]
});
// You can sort in reverse order like this
db.find({ system: 'solar' }).sort({ planet: -1 }).exec(function (err, docs) {
// docs is [doc1, doc3, doc2]
});
// You can sort on one field, then another, and so on like this:
db.find({}).sort({ firstField: 1, secondField: -1 }) ... // You understand how this works!
You can give find
and findOne
an optional second argument, projections
. The syntax is the same as MongoDB: { a: 1, b: 1 }
to return only the a
and b
fields, { a: 0, b: 0 }
to omit these two fields. You cannot use both modes at the time, except for _id
which is by default always returned and which you can choose to omit.
// Same database as above
// Keeping only the given fields
db.find({ planet: 'Mars' }, { planet: 1, system: 1 }, function (err, docs) {
// docs is [{ planet: 'Mars', system: 'solar', _id: 'id1' }]
});
// Keeping only the given fields but removing _id
db.find({ planet: 'Mars' }, { planet: 1, system: 1, _id: 0 }, function (err, docs) {
// docs is [{ planet: 'Mars', system: 'solar' }]
});
// Omitting only the given fields and removing _id
db.find({ planet: 'Mars' }, { planet: 0, system: 0, _id: 0 }, function (err, docs) {
// docs is [{ inhabited: false, satellites: ['Phobos', 'Deimos'] }]
});
// Failure: using both modes at the same time
db.find({ planet: 'Mars' }, { planet: 0, system: 1 }, function (err, docs) {
// err is the error message, docs is undefined
});
// You can also use it in a Cursor way but this syntax is not compatible with MongoDB
// If upstream compatibility is important don't use this method
db.find({ planet: 'Mars' }).projection({ planet: 1, system: 1 }).exec(function (err, docs) {
// docs is [{ planet: 'Mars', system: 'solar', _id: 'id1' }]
});
See Issue from @adityamukho
You can use count
to count documents. It has the same syntax as find
. For example:
// Count all planets in the solar system
db.count({ system: 'solar' }, function (err, count) {
// count equals to 3
});
// Count all documents in the datastore
db.count({}, function (err, count) {
// count equals to 4
});
db.update(query, update, options, callback)
will update all documents matching query
according to the update
rules:
query
is the same kind of finding query you use withfind
andfindOne
update
specifies how the documents should be modified. It is either a new document or a set of modifiers (you cannot use both together, it doesn't make sense!)- A new document will replace the matched docs
- The modifiers create the fields they need to modify if they don't exist, and you can apply them to subdocs. Available field modifiers are
$set
to change a field's value,$unset
to delete a field and$inc
to increment a field's value. To work on arrays, you have$push
,$pop
,$addToSet
,$pull
, and the special$each
. See examples below for the syntax.
options
is an object with two possible parametersmulti
(defaults tofalse
) which allows the modification of several documents if set to trueupsert
(defaults tofalse
) if you want to insert a new document corresponding to theupdate
rules if yourquery
doesn't match anything. If yourupdate
is a simple object with no modifiers, it is the inserted document. In the other case, thequery
is stripped from all operator recursively, and theupdate
is applied to it.
callback
(optional) signature:err
,numReplaced
,newDoc
numReplaced
is the number of documents replacednewDoc
is the created document if the upsert mode was chosen and a document was inserted
Note: you can't change a document's _id.
// Let's use the same example collection as in the "finding document" part
// { _id: 'id1', planet: 'Mars', system: 'solar', inhabited: false }
// { _id: 'id2', planet: 'Earth', system: 'solar', inhabited: true }
// { _id: 'id3', planet: 'Jupiter', system: 'solar', inhabited: false }
// { _id: 'id4', planet: 'Omicron Persia 8', system: 'futurama', inhabited: true }
// Replace a document by another
db.update({ planet: 'Jupiter' }, { planet: 'Pluton'}, {}, function (err, numReplaced) {
// numReplaced = 1
// The doc #3 has been replaced by { _id: 'id3', planet: 'Pluton' }
// Note that the _id is kept unchanged, and the document has been replaced
// (the 'system' and inhabited fields are not here anymore)
});
// Set an existing field's value
db.update({ system: 'solar' }, { $set: { system: 'solar system' } }, { multi: true }, function (err, numReplaced) {
// numReplaced = 3
// Field 'system' on Mars, Earth, Jupiter now has value 'solar system'
});
// Setting the value of a non-existing field in a subdocument by using the dot-notation
db.update({ planet: 'Mars' }, { $set: { "data.satellites": 2, "data.red": true } }, {}, function () {
// Mars document now is { _id: 'id1', system: 'solar', inhabited: false
// , data: { satellites: 2, red: true }
// }
// Not that to set fields in subdocuments, you HAVE to use dot-notation
// Using object-notation will just replace the top-level field
db.update({ planet: 'Mars' }, { $set: { data: { satellites: 3 } } }, {}, function () {
// Mars document now is { _id: 'id1', system: 'solar', inhabited: false
// , data: { satellites: 3 }
// }
// You lost the "data.red" field which is probably not the intended behavior
});
});
// Deleting a field
db.update({ planet: 'Mars' }, { $unset: { planet: true } }, {}, function () {
// Now the document for Mars doesn't contain the planet field
// You can unset nested fields with the dot notation of course
});
// Upserting a document
db.update({ planet: 'Pluton' }, { planet: 'Pluton', inhabited: false }, { upsert: true }, function (err, numReplaced, upsert) {
// numReplaced = 1, upsert = { _id: 'id5', planet: 'Pluton', inhabited: false }
// A new document { _id: 'id5', planet: 'Pluton', inhabited: false } has been added to the collection
});
// If you upsert with a modifier, the upserted doc is the query modified by the modifier
// This is simpler than it sounds :)
db.update({ planet: 'Pluton' }, { $inc: { distance: 38 } }, { upsert: true }, function () {
// A new document { _id: 'id5', planet: 'Pluton', distance: 38 } has been added to the collection
});
// If we insert a new document { _id: 'id6', fruits: ['apple', 'orange', 'pear'] } in the collection,
// let's see how we can modify the array field atomically
// $push inserts new elements at the end of the array
db.update({ _id: 'id6' }, { $push: { fruits: 'banana' } }, {}, function () {
// Now the fruits array is ['apple', 'orange', 'pear', 'banana']
});
// $pop removes an element from the end (if used with 1) or the front (if used with -1) of the array
db.update({ _id: 'id6' }, { $pop: { fruits: 1 } }, {}, function () {
// Now the fruits array is ['apple', 'orange']
// With { $pop: { fruits: -1 } }, it would have been ['orange', 'pear']
});
// $addToSet adds an element to an array only if it isn't already in it
// Equality is deep-checked (i.e. $addToSet will not insert an object in an array already containing the same object)
// Note that it doesn't check whether the array contained duplicates before or not
db.update({ _id: 'id6' }, { $addToSet: { fruits: 'apple' } }, {}, function () {
// The fruits array didn't change
// If we had used a fruit not in the array, e.g. 'banana', it would have been added to the array
});
// $pull removes all values matching a value or even any NeDB query from the array
db.update({ _id: 'id6' }, { $pull: { fruits: 'apple' } }, {}, function () {
// Now the fruits array is ['orange', 'pear']
});
db.update({ _id: 'id6' }, { $pull: { fruits: $in: ['apple', 'pear'] } }, {}, function () {
// Now the fruits array is ['orange']
});
// $each can be used to $push or $addToSet multiple values at once
// This example works the same way with $addToSet
db.update({ _id: 'id6' }, { $push: { fruits: {$each: ['banana', 'orange'] } } }, {}, function () {
// Now the fruits array is ['apple', 'orange', 'pear', 'banana', 'orange']
});
db.remove(query, options, callback)
will remove all documents matching query
according to options
query
is the same as the ones used for finding and updatingoptions
only one option for now:multi
which allows the removal of multiple documents if set to true. Default is falsecallback
is optional, signature: err, numRemoved
// Let's use the same example collection as in the "finding document" part
// { _id: 'id1', planet: 'Mars', system: 'solar', inhabited: false }
// { _id: 'id2', planet: 'Earth', system: 'solar', inhabited: true }
// { _id: 'id3', planet: 'Jupiter', system: 'solar', inhabited: false }
// { _id: 'id4', planet: 'Omicron Persia 8', system: 'futurama', inhabited: true }
// Remove one document from the collection
// options set to {} since the default for multi is false
db.remove({ _id: 'id2' }, {}, function (err, numRemoved) {
// numRemoved = 1
});
// Remove multiple documents
db.remove({ system: 'solar' }, { multi: true }, function (err, numRemoved) {
// numRemoved = 3
// All planets from the solar system were removed
});
NeDB supports indexing. It gives a very nice speed boost and can be used to enforce a unique constraint on a field. You can index any field, including fields in nested documents using the dot notation. For now, indexes are only used to speed up basic queries and queries using $in
, $lt
, $lte
, $gt
and $gte
.
To create an index, use datastore.ensureIndex(options, cb)
, where callback is optional and get passed an error if any (usually a unique constraint that was violated). ensureIndex
can be called when you want, even after some data was inserted, though it's best to call it at application startup. The options are:
- fieldName (required): name of the field to index. Use the dot notation to index a field in a nested document.
- unique (optional, defaults to
false
): enforce field uniqueness. Note that a unique index will raise an error if you try to index two documents for which the field is not defined. - sparse (optional, defaults to
false
): don't index documents for which the field is not defined. Use this option along with "unique" if you want to accept multiple documents for which it is not defined.
Note: the _id
is automatically indexed with a unique constraint, no need to call ensureIndex
on it.
You can remove a previously created index with datastore.removeIndex(fieldName, cb)
.
If your datastore is persistent, the indexes you created are persisted in the datafile, when you load the database a second time they are automatically created for you. No need to remove any ensureIndex
though, if it is called on a database that already has the index, nothing happens.
db.ensureIndex({ fieldName: 'somefield' }, function (err) {
// If there was an error, err is not null
});
// Using a unique constraint with the index
db.ensureIndex({ fieldName: 'somefield', unique: true }, function (err) {
});
// Using a sparse unique index
db.ensureIndex({ fieldName: 'somefield', unique: true, sparse: true }, function (err) {
});
// Format of the error message when the unique constraint is not met
db.insert({ somefield: 'nedb' }, function (err) {
// err is null
db.insert({ somefield: 'nedb' }, function (err) {
// err is { errorType: 'uniqueViolated'
// , key: 'name'
// , message: 'Unique constraint violated for key name' }
});
});
// Remove index on field somefield
db.removeIndex('somefield', function (err) {
});
Note: the ensureIndex
function creates the index synchronously, so it's best to use it at application startup. It's quite fast so it doesn't increase startup time much (35 ms for a collection containing 10,000 documents).
As of v0.8.0, you can use NeDB in the browser! You can find it and its minified version in the repository, in the browser-version/out
directory. You only need to require nedb.js
or nedb.min.js
in your HTML file and the global object Nedb
can be used right away, with the same API as the server version:
<script src="nedb.min.js"></script>
<script>
var db = new Nedb(); // Create an in-memory only datastore
db.insert({ planet: 'Earth' });
db.insert({ planet: 'Mars' });
db.find({}, function (err, docs) {
// docs contains the two planets Earth and Mars
});
</script>
It has been tested and is compatible with Chrome, Safari, Firefox, IE 10, IE 9. Please open an issue if you need compatibility with IE 8/IE 7, I think it will need some work and am not sure it is needed, since most complex webapplications - the ones that would need NeDB - only work on modern browsers anyway. To launch the tests, simply open the file browser-version/test/index.html
in a browser and you'll see the results of the tests for this browser.
If you fork and modify nedb, you can build the browser version from the sources, the build script is browser-version/build.js
.
As of v0.11, NeDB is also persistent on the browser. To use this, simply create the collection with the filename
option which will be the name of the localStorage
variable storing data. Persistence should work on all browsers where NeDB works. Also, keep in mind that localStorage
has size constraints, so it's probably a good idea to set recurring compaction every 2-5 minutes to save on space if your client app needs a lot of updates and deletes. See database compaction for more details on the append-only format used by NeDB.
Browser persistence is still young! It has been tested on most major browsers but please report any bugs you find
NeDB is not intended to be a replacement of large-scale databases such as MongoDB, and as such was not designed for speed. That said, it is still pretty fast on the expected datasets, especially if you use indexing. On my machine (3 years old, no SSD), with a collection containing 10,000 documents, with indexing:
- Insert: 5,950 ops/s
- Find: 25,440 ops/s
- Update: 4,490 ops/s
- Remove: 6,620 ops/s
You can run the simple benchmarks I use by executing the scripts in the benchmarks
folder. Run them with the --help
flag to see how they work.
A copy of the whole database is kept in memory. This is not much on the expected kind of datasets (20MB for 10,000 2KB documents). If requested, I'll introduce an option to not use this cache to decrease memory footprint (at the cost of a lower speed).
- connect-nedb-session is a session store for Connect and Express, backed by nedb
- If you mostly use NeDB for logging purposes and don't want the memory footprint of your application to grow too large, you can use NeDB Logger to insert documents in a NeDB-readable database
- If you've outgrown NeDB, switching to MongoDB won't be too hard as it is the same API. Use this utility to transfer the data from a NeDB database to a MongoDB collection
Issues reporting and pull requests are always appreciated. For issues, make sure to always include a code snippet and describe the expected vs actual behavior. If you send a pull request, make sure to stick to NeDB's coding style and always test all the code you submit. You can look at the current tests to see how to do it
You don't have time? You can support NeDB by sending bitcoins to this adress:
See License