Query examples

Every query example on this page is in one of the queryTests modules of the DocCode. The tests are yours to explore and modify. Please send us your feedback and contributions.

Setup

// Set convenience variables with 
// commonly used Breeze query classes 
var EntityQuery = breeze.EntityQuery;
var FilterQueryOp = breeze.FilterQueryOp;
var Predicate = breeze.Predicate;

// create a manager to execute queries
var manager = new breeze.EntityManager(serviceName);

Basic queries

// 3 equivalent queries for "all Customers"
var query1a = EntityQuery.from('Customers');   

var query1b = new EntityQuery('Customers');   

var query1c = new EntityQuery().from('Customers');

// execute one of them
manager.executeQuery(query1a) // returns a promise
     .then(querySucceeded)  // process results
     .fail(queryFailed);    // handle error

Filtering with "where"

Simple conditions

// query for Customers whose names start with "A";
// using the 'startsWith' operator
var query1 = EntityQuery.from('Customers')
    .where('CompanyName', 'startsWith', 'A');

// this time, use the FilterQueryOp enum
var query = EntityQuery.from('Customers')
    .where('CompanyName', FilterQueryOp.StartsWith, 'A');

// Orders with freight costs >  $100
var query = EntityQuery.from('Orders')
    .where('Freight', '>', 100);

// this time, use the FilterQueryOp enum
var query = EntityQuery.from('Orders')
    .where('Freight', FilterQueryOp.GreaterThan, 100);

// Orders ordered after February 1, 1998
// (n.b.: month numbers start at zero in JavaScript)
var query = EntityQuery.from('Orders')
    .where('OrderDate', '>', new Date(1998, 1, 1)) 

// Orders with no (null) OrderDate
var query = EntityQuery.from('Orders')
    .where('OrderDate', '==', null); 

// Orders shipped after they were supposed to be delivered
// Compares two fields of the same record
var query = EntityQuery.from("Orders")
        .where("ShippedDate", ">", "RequiredDate");

// Customers whose name contains the word, "market";
var query = EntityQuery.from('Customers')
     .where('CompanyName', FilterQueryOp.Contains, 'market'); 

Compound conditions with predicates

// Start with a base query for all Orders
var baseQuery = EntityQuery.from('Orders');

// A Predicate is a condition that is true or false
// Combine two predicates with '.and' to
// query for orders with freight cost over $100
// that were ordered after April 1, 1998
var p1 = new Predicate('Freight', '>;', 100);
var p2 = new Predicate('OrderDate', '>', new Date(1998, 3, 1));
var query1a = baseQuery.where(p1.and(p2));

// "AND" them together using an array
var p1 = Predicate.create('Freight', '>', 100)
var p2 = Predicate.create('OrderDate', '>', new Date(1998, 3, 1));
var pred = Predicate.and([p1, p2]);
var query1b = baseQuery.where(pred);

// Yet another way to ask the same question
var pred = Predicate
       .create('Freight', '>;', 100)
       .and('OrderDate', '>;', new Date(1998, 3, 1));
var query1c = baseQuery.where(pred);

// Use the "or" operator to query for Orders
// EITHER with Freight over $100
// OR that were ordered after April 1, 1998
var pred = Predicate
       .create('Freight', '>;', 100)
       .or('OrderDate', '>;', new Date(1998, 3, 1));
var query2 = baseQuery.where(pred);

// Compose multiple predicates **left-to-right** 
// Here we OR a date range then AND the Freight-over-100 constraint
var pred = Predicate
      .create('OrderDate', '>=', new Date(Date.UTC(1996, 0, 1))) // Jan===0 in JavaScript
      .or(    'OrderDate', '<',  new Date(Date.UTC(1997, 0, 1)))
      .and(   'Freight',   '>',  100);
var query2b = baseQuery.where(pred);

/*
 The `create` call predicate creates the date-gte predicate

 The `or` call returns a predicate which is the OR of the 1st predicate and 
 the 2nd date condition. This is the OR predicate

 The third `and` call returns the AND of the OR-predicate and the freight condition.

 also using new Date(Date.UTC(...)) to create unambiguous UTC date value with no time component.
*/

// Negate a predicate for Orders with Freight over $100
// using the 'not' operator
var basePred = Predicate.create('Freight', '>;', 100);
var pred = basePred.not();

// Negate it again, using 'Predicate.not' 
var pred = Predicate.not(basePred)

// apply the predicate
var query3 = baseQuery.where(pred);

You can display the OData query clause that such predicates will emit with the following "trick":

// Get an EntityType. Any EntityType will usually do but we'll use the Order type
var orderType = manager.metadataStore.getEntityType('Order')); 
console.log("OData predicate: " + pred.toODataFragment(orderType ));

The composed predicate shown above ...

var pred = Predicate
      .create('OrderDate', '>=', new Date(Date.UTC(1996, 0, 1))) // Jan===0 in JavaScript
      .or(    'OrderDate', '<',  new Date(Date.UTC(1997, 0, 1)))
      .and(   'Freight',   '>',  100);

prints as follows:

OData predicate: ((OrderDate ge datetime'1996-01-01T00:00:00.000Z') or (OrderDate lt datetime'1997-01-01T00:00:00.000Z')) and (Freight gt 100)

Conditions on related properties

// Products in a Category whose name starts with "S"
var query1 = EntityQuery.from('Products')
    .where('Category.CategoryName', 'startswith', 'S')

// Orders sold to a Customer located in California
var query2 = EntityQuery.from('Orders')
    .where('Customer.Region', '==', 'CA');

Conditions involving any/all with related properties

Breeze supports two filter operators that support the ability to perform 'Any' and 'All' queries.

The two operators are:

  • FilterQueryOp.Any - aliases: "any", "some"
  • FilterQueryOp.All - aliases: "all", "every"

Examples:

The following query attempts to find any "Employees" who have placed any orders with a 'freightCost' of more than $950.

var query = EntityQuery.from("Employees")
    .where("orders", "any", "freightCost",  ">", 950);   

The same query can be composed using a FilterQueryOps directly:

var query = EntityQuery.from("Employees")
    .where("orders", FilterQueryOp.Any, "freightCost",  FilterQueryOp.GreaterThan, 950);   

or by using the 'some' alias.

var query = EntityQuery.from("Employees")
    .where("orders", "some", "freightCost",  ">", 950);

It can also be built up in pieces.

var predicate = Predicate.create("freightCost", ">", 950);
var query = EntityQuery.from("Employees")
    .where("orders", FilterQueryOp.Any, predicate);

More complicated predicates can also be used. For example to filter for all customers that do not have any orders.

var p = Predicate.create("orders", "any", "id", "!=", null).not();
var query = EntityQuery.from("Customers").where(p);

or to query for all Employees that have at least one order with a customer whose name starts with 'Lazy"

var query = EntityQuery.from("Employees")
       .where("orders", "any", "customer.companyName", "startsWith", "Lazy")
       .expand("orders.customer");

Composite predicates can be used as well.

var p = Predicate.create("freight", ">", 950).and("shipCountry", "startsWith", "G");
var query = EntityQuery.from("Employees")
   .where("orders", "any", p)
   .expand("orders");

and Predicates can even be nested. In this case we are querying for any orders where every orderDetail has a unit price of more than $200.00.

var q1 = EntityQuery.from("Customers")
  .where("orders", "any", "orderDetails", "all", "unitPrice", ">", 200);

Conditions using OData functions

// Customers whose Company names starts with "C" or "c";
var query1 = EntityQuery.from('Customers')
    .where('toLower(CompanyName)', 'startsWith', 'c');

// Customers whose 2nd and 3rd letters are 'om'
var query2 = EntityQuery.from('Customers')
    .where('toUpper(substring(CompanyName, 1, 2))', '==', 'OM');

Sorting with 'orderBy'

Single property sort

// Products in ascending name order
var query1 = EntityQuery.from('Products')
    .orderBy('ProductName');

// Products in descending name order
var query2a = EntityQuery.from('Products')
    .orderBy('ProductName desc');

// Products in descending name order (version 2)
var query2a = EntityQuery.from('Products')
    .orderByDesc('ProductName');

Multiple property sort

// Products sorted from highest to lowest price, then by name
var query1 = EntityQuery.from('Products')
    .orderBy('UnitPrice desc,ProductName');

Related property sorting

// Products sorted by their Category names (in descending order)
var query1 = EntityQuery.from('Products')
    .orderBy('Category.CategoryName desc');

// Products sorted by their Category names, then by Product name (in descending order)
var query2 = EntityQuery.from('Products')
    .orderBy('Category.CategoryName, ProductName desc');

Paging with 'skip' and 'take'

// Get the first 5 Products
var query1 = EntityQuery.from('Products')
    .take(5);

// Get the first 5 Products beginning with &#39;C&#39;
// and also get the total of all products beginning with &#39;C&#39;
var query2 = EntityQuery.from('Products')
    .where('ProductName', 'startsWith', 'C')
    .take(5)
    .inlineCount();

manager.executeQuery(query2)
    .then(function(data) {
        var pages = Math.ceil(data.inlineCount / 5);
        // do something with data.results
    });

// Skip the first 10 Products and return the rest
var query3 = EntityQuery.from('Products')
    .orderBy('ProductName')
    .skip(10);

// Get the 3rd page of 5 Products
// by skipping 10 Products and taking the next 5
var query4 = EntityQuery.from('Products')
    .orderBy('ProductName')
    .skip(10)
    .take(5);

// Take the first 10 Products after
// sorting them by their Category names in descending order
var query5 = EntityQuery.from('Products')
    .orderBy('Category.CategoryName desc');
    .take(10);

Projection with 'select'

Single data property projections

// just the names of the Customers that begin with &#39;C&#39;
var query = EntityQuery.from('Customers')
     .where('CompanyName', 'startsWith', 'C')
     .select('CompanyName');

Single navigation property projections

// Orders of the Customers that begin with &#39;C&#39;
var query = EntityQuery.from('Customers')
     .where('CompanyName', 'startsWith', 'C')
     .select('Orders');

Multiple property projections

// Selected properties of customers with names starting with "C"
var query = EntityQuery.from('Customers')
    .where('CompanyName', FilterQueryOp.StartsWith, 'C')
    .select('CustomerID_OLD, CompanyName, ContactName')
    .orderBy('CompanyName');

Related property projections

// Names of customers with orders that have excessive freight costs
var query = EntityQuery.from('Orders')
    .where('Freight', FilterQueryOp.GreaterThan, 500)
    .select('Customer.CompanyName')
    .orderBy('Customer.CompanyName');

Eager loading with 'expand'

Single relation expand

// include the Category in the payload for
// Products whose Category names start with &#39;S&#39;
var query = EntityQuery.from('Products')
    .where('Category.CategoryName', 'startswith', 'S')
    .expand('Category');

Query by key with expand

// Query for Customer with ID 42
// Like manager.fetchEntityByKey('Customer', 42)
// (as shown below) except expanded to include related Orders.
var query = EntityQuery.from('Customers')
    .where('CustomerID', 'eq', 42)
    .expand('Orders');

Multiple relation expand

// include both the parent Customers and child OrderDetails
// in the payload of a query for the first 20 Orders
var query = EntityQuery.from('Orders')
    .take(20)
    .expand('Customer, OrderDetails');

Property path expand

// include the OrderDetails and their parent Products
// in the payload of a query for the first 20 Orders
// using a property path
var query = new EntityQuery('Orders')
       .take(20)
       .expand('OrderDetails.Product');

Query by key

Call fetchEntityByKey directly on the EntityManager. Note the 'fetch' prefix.

// Fetch the customer with CustomerID == 42 from the database
// returns a promise. 
manager.fetchEntityByKey('Customer', 42)
   .then(fetchSucceeded).fail(fetchFailed);

See example above to expand with related entities.

Add checkLocalCacheFirst=true parameter to look in the cache first and query the database if not found.

// Look for the customer in manager&#39;s cache first
// Fetch from the database if not found in cache
manager.fetchEntityByKey('Customer', 42, true) 
   .then(fetchSucceeded).fail(fetchFailed);

Call getEntityByKey directly on the EntityManager to extract the entity from cache. Note the 'get' prefix.This isn't really a query because it can only look in cache and never calls the remote service. It returns immediately with the entity or null.

// Look for entity only in cache. 
// Returns value (or null) immediately
var customer = manager.getEntityByKey('Customer', 42);

Query a bag of entities

A 'query' can return an object filled with arbitrary collections of entities. Particularly useful when you want to prime your cache with lookup lists. Start on the server with a service query method that returns an object whose properties contain lists of entities. Here's a Web API controller method example:

[HttpGet]
public object Lookups()
{
    var regions = _contextProvider.Context.Regions;
    var territories = _contextProvider.Context.Territories;
    var categories = _contextProvider.Context.Categories;

    var lookups = new {regions, territories, categories};
    return lookups;
}

On the JavaScript client:

// Fetch the lookups; ignores the results; entities are in cache
// see the DocCode queryTests module for details
EntityQuery.from('Lookups')
     .using(em).execute()
     .fail(handleFail);

The Region, Territory, and Category entities are in cache after the query succeeds. See 'Lookup Lists' for a richer discussion of this example.