To create a query use select(). You must pass the entity identifier:
var events_query = client.select('event')
Optionally you can use BQL queries. The first argument is the BQL query and the second parameter is optional. It can be a single value, an array of values or just multiple arguments
events_query.query('join place') // BQL without parameters
events_query.query('where type=?', 'conference') // one parameter
events_query.query('where type=? and start_date>?', 'conference', new Date()) // multiple arguments
events_query.query('where type=? and start_date>?', ['conference', new Date()]) // array
Use fetch() to retrieve the results of the query. This method needs three arguments. The first is the limit of objects to be returned. The second is the offset, and the third argument is a callback function with three arguments. Callbacks always receive an error as the first parameter. This parameter is null if everything is ok. The second argument in this case is an array of objects (the result of the query). And finally you receive the total count of objects of the query (the total number of objects without pagination).
events_query.fetch(10, 0, function(err, objects, totalCount, fromCache) {
// do something with these objects
})
`
objects is the array of results and totalCount is the total number of objects matching the query. For example there could be 1000 objects matching the query but since you requested a maximum of 10 objects the objects array has 10 objects and totalCount is equal to 1000.
Query objects support chained method calls, so you can do everything in a single line:
backbeam.select('event').query('join place').fetch(10, 0, function(err, objects, totalCount, fromCache) {
// do something
})
There is a helper object to create collection constraints when using the in operator in a query.
var collection = backbeam.collection(someUser)
.addTwitter(someTwitterId)
.addFacebook(someFacebookId)
.addGooglePlus(someGooglePlusId)
.addEmail('user@example.com')
backbeam.select('user').query('where this in ?', collection)
The backbeam.collection() method accepts one or many objects or even an array of objects. You can also use identifiers (strings) directly. If you want to add constraints related to users you can add Twitter, Facebook, Google+, LinkedIn or GitHub identifiers or email addresses using the methods: addTwitter, addFacebook, addGooglePlus, addLinkedIn, addGitHub and addEmail that also support one or many strings of identifiers or an array of identifiers.
It is easy to refresh the data of a given object. You just need to call the refresh method.
var obj = backbeam.empty('place', known_id)
obj.refresh('join events having something = ?', someValue, function(error) {
// here the object is populated with its values if no error ocurred
})
The query and query parameters are optional. You can just pass the callback.
You can also do the same in just one step with the backbeam.read method. Example:
backbeam.read('place', known_id, 'join events having something = ?', someValue, function(error, obj) {
// here the object is populated with its values if no error ocurred
})
The mandatory parameters are the entity identifier, the object identifier and the callback. The joins and its parameters are optionals. And you can also perform joins without arguments.
You can create an empty object and then save it as follows:
var obj = backbeam.empty('place')
obj.set('some-field', some_value)
obj.save(function(error) {
// here the object has been created and you can access its id(), createdAt() and updatedAt() methods
})
You can delete an object using the remove() method.
var obj = ... // some object from the database
obj.remove(function(error) {
// object deleted if there were no errors
})
Do not confuse this mehtod with rem(fieldName, object). The latter is used to remove an object from a relationship. We wanted to avoid the confusion using delete as name for the method to delete an object from the database, but delete is a keyword in JavaScript.