Getting Started

Basics

Query Modifiers

.where() .sort()

Query Predicates

.equals() .notEquals() .exists() .notExists() .startsWith() .endsWith() .contains() .greaterThan() .lessThan() .between() .outside()

Query Executors

.read() .first() .last() .count() .sum() .average() .min() .max() .update() .delete()

Login Methods

.exists() .login() .logout()

Instance Methods

.read() .delete()

Instance Login Methods

.login() .logout() .changePassword()

Misc

Back.then() Back.saved() Back.user() Back.eachProperty() Back.eachDescendant() IFile Property LoginResult

Predicates.exists()

Filters the query based on whether the applicable FileProperty or InstancelProperty is unequal to null.

Employees
	.where(Employee.avatar).exists()
	.read(employees =>
	{
		// employees is an array of Employee objects 
		// that have an avatar image.
	});

Method signature (TypeScript)

static exists();

Details

returns
An object containing all of the Query Modifiers and Query Executors.

Availability:

This predicate is available when the previous .where() modifier contains a property of one of the following types: