Collection

Represents a collection of database objects. Note that it will not contain any objects by itself. Instead, it yields a preparation for how to execute a DB query. A query will be executed when calling methods that returns a Promise, such as toArray() or each().

Inheritance Hierarchy

• Collection
  • WriteableCollection

Construction

Collection constructor is private. Instances are returned from the WhereClause methods and some of the Table methods.

Samples

// each()
var collection = db.friends.where('name').equalsIgnoreCase('david');

collection.each(function(friend) {
    console.log('Found: ' + friend.name + ' with phone number ' + friend.phone);
});

// toArray()
db.friends.where('name').startsWithIgnoreCase('d').toArray(function(friends) {
    console.log("Found " friends.length + " friends starting with d");
});

// offset/limit
db.friends
  .where('age').above(25)
  .offset(10)
  .limit(10)
  .toArray(function (friends) {
    console.log(friends.map(JSON.stringify).join('\n'));
  });

// count
db.friends.toCollection().count(function (count) {
    console.log(count + " friends in total");
});

// or
db.friends
  .where('age').above(25)
  .or('shoeSize').above(9)
  .each (function (friend) {
    console.log("Found big friend: " + friend.name);
  });

Methods

and()

Add JS based criteria to collection

clone()

Clone the query before manipulating it further (Does not clone database items).

count()

Get the number of items in the collection

desc()

Sort in descending order

distinct()

Remove duplicates of items with same primary key

each()

Execute query and call a function for each item

eachKey()

Execute query on the index or primary key being used and call a function for each key

eachPrimaryKey()

Execute query on the index and call a function for each primary key that corresponds to the index.

eachUniqueKey()

Execute query on the index or primary key being used and call a function for each unique key

filter()

Filter objects

first()

Get the first item in the collection

keys()

Retrieve an array containing all keys of the collection (index or primary key depending on where() clause)

last()

Get the last item in the collection

limit()

Limit the result to given number of items

offset()

Ignore N items before given offset and return the rest

or()

Logical OR operation

primaryKeys()

Retrieve an array containing all primary keys of the collection

raw()

Don't filter results through reading hooks

reverse()

Reverse the order of items.

sortBy()

Execute query and get an array with the results sorted by given property

toArray()

Execute query and get an array with the results sorted by the index used in the where() clause

uniqueKeys()

Retrieve an array containing all unique keys of the collection (index or primary key depending on where() clause)

until()

Ignores items occurring after given filter returns true.