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Show / Hide Table of Contents
  • Programmer's Guide
  • Client Side API Programming
    • Setting Up Development Environment
    • Basic Cache Operations
      • Initialize Cache
      • Add Data to Cache
      • Update Data in Cache
      • Fetch Data From Cache
      • Remove Data From Cache
      • Dispose Cache
    • Bulk Operations
      • Adding Collection to Cache
      • Updating Collection in Cache
      • Retrieving Collection from Cache
      • Removing Collection from Cache
      • Deleting Collection from Cache
    • Asynchronous Operations
      • Using Asynchronous Operations
      • Using Asynchronous Operations with Callback Methods
    • Groups and Subgroups
      • Adding/Updating Data Group in Cache
      • Retrieving Data Group from Cache
      • Removing Data Group from Cache
    • Tagging Data in NCache
      • Creating Tags
      • Adding Items with Tags
      • Retrieving Previously Tagged Data
      • Removing Tagged Items from Cache
    • Named Tags
    • Data Expiration Strategies
      • Using Absolute Expiration
      • Using Sliding Expiration
    • Cache Dependencies
      • Key Dependency
      • File Dependency
      • Notification based Dependencies
        • Database Dependency using SQL Server
        • Database Dependency using Oracle
      • Polling Based Dependency
      • Custom Data Source Dependency
      • Multiple Cache Sync Dependency
      • Aggregate Dependency
      • Add Dependency to Existing Item
      • Using CLR Procedures to Call NCache
    • Locking Data in NCache
      • Locking Items in Cache (Pessimistic Locking)
      • Locking Items with Cache Item Versioning (Optimistic Locking)
    • SQL Reference for NCache
      • SQL Syntax
      • Querying Samples for Operators
      • Querying Data in NCache
      • NCache Language Integrated Query (LINQ)
        • Using LINQ in NCache
        • Configuring LINQPad for NCache
        • Querying NCache Data in LINQPad
    • Event Notifications
      • Cache Level Event Notifications
      • Item Level Event Notifications
      • Custom Event Notifications
    • Publish/Subscribe (Pub/Sub) in NCache
      • Pub/Sub Topics
      • Managing Topics
      • Pub/Sub Messages
        • Message Behavior and Properties
        • Creating a Message
      • Publish Messages to Topic
      • Subscribe for Topic Messages
      • Monitoring Pub/Sub Topics
    • Continuous Query
    • Using Streams in NCache
      • Opening with Stream Modes
      • Adding and Updating Data with Streams
      • Retrieving Data from Streams
      • Closing a Stream
    • Security and Encryption
      • NCache Security
      • NCache Data Encryption
    • Data Compression
    • NCache Management API
  • Server Side API Programming
    • Cache Startup Loader
      • Components of Cache Startup Loader
      • Sample Implementation of ICacheLoader on Single Node
      • Sample Implementation of ICacheLoader with Distribution Hints
    • Data Source Providers (Backing Source)
      • Read-Through Caching
        • Configure Read-Through Provider
        • Using Read-Through with Cache Operations
      • Write-Through Caching
        • Configuring Write-Through Provider
        • Using Write-Through with Basic Operations
        • Using Write-Behind with Basic Operations
        • Using Write-Behind with Bulk Operations
        • Using Write-Behind with Async Operations
        • Monitor Write-Through Counters
    • Custom Dependency
      • Sample Implementation of Custom Dependency
      • Sample Usage of Custom Dependency
    • WAN Replication through Bridge
      • Bridge Configurations
      • Implementing Bridge Conflict Resolver
    • Entry Processor
      • Sample Implementation of IEntryProcessor Interface
      • Sample Usage of EntryProcessor
    • MapReduce
      • Sample Implementation of MapReduce Interfaces
      • Sample Usage of MapReduce
    • Aggregator
      • Sample Implementation of IValueExtractor Interface
      • Sample Implementation of IAggregator Interface
      • Sample Usage of Aggregator
    • Dynamic Compact Serialization
  • Client Side ASP.NET Features
    • ASP.NET
      • ASP.NET Session State Provider for NCache
      • Multi-Region ASP.NET Session State Provider for NCache
    • ASP.NET Core
      • Session Storage in ASP.NET Core
        • Configure NCache ASP.NET Core Session Provider
        • Configure ASP.NET Core Sessions with NCache IDistributedCache Provider
      • Multi-Region ASP.NET Core Session Provider for NCache
      • Object Caching in ASP.NET Core
    • ASP.NET SignalR
      • Using NCache Extension for SignalR
    • View State Caching
      • Configuring and Using Content Optimization
      • Group View State with Sessions
      • Limit View State Caching
      • Perform Page Level Grouping for View State
    • ASP.NET Output Cache
      • Configure ASP.NET Output Caching
      • Using ASP.NET Output Cache with Custom Hooks
  • Client Side Third Party Integrations
    • Migrating AppFabric to NCache
      • AppFabric API vs. NCache API
    • NHibernate
      • NCache as NHibernate Second Level Cache
      • Using NHibernate Query Caching
      • Configuring Database Synchronization with NHibernate
    • Entity Framework Caching Integration
      • NCache as Entity Framework Second Level Cache
      • Entity Framework Caching Config File
    • Entity Framework Core Caching
      • Installing NCache Entity Framework Core Provider
      • Configuring NCache Entity Framework Core Provider
      • Using NCache Entity Framework Core Provider
        • Caching Options for EF Core Provider
        • LINQ APIs for EF Core Provider
        • Cache Only APIs for EF Core Provider
        • Query Deferred APIs for EF Core Provider
      • Logging in NCache Entity Framework Core Provider
    • Memcached
      • NCache Memcached Gateway Approach
      • Memcached Client Plugin for .NET
    • Debug NCache Providers in Visual Studio
    • NCache for Visual Studio Extension

NCache Language Integrated Query (LINQ)

LINQ allows fetching data of any type through a set of pre-defined standard rules. This helps in setting a common standard through which data can be accessed. It simply joins the application's object layer to data layer. Data can be retrieved in collection of any possible data structure like objects, XML tree, lists, but there will be no change in the retrieval format of code. If the model is created through LINQ, then there is no need to worry about inner details.

NCache allows using LINQ with cache to improve the application’s performance through caching without changing the LINQ object model. The cache handle should be given to the NCache LINQ provider after creating its instance. NCache LINQ provider converts LINQ related query into NQL format and returns the result accordingly after transforming it in LINQ format. Because of using NQL under the wrapper of NCache LINQ provider, indexes should be configured for using LINQ too.

Here is a sample query in LINQ:

var result = from product in products
where product.ProductID > 10
select product;

In this query, all those products which have ProductID greater than 10 will be fetched from the cache. The query format is the same as when normal LINQ is used without NCache LINQ provider. Here ProductID and other required attributes need to be indexed before using this query with NCache.

There are some LINQ operators which are not supported by NCache LINQ Provider. Those are:

  • NCache LINQ Provider does not support nested queries.
  • LINQ operator ORDER BY is not supported by NCache LINQ Provider.
  • LINQ operator GROUP BY is not supported by NCache LINQ Provider.
  • JOIN operations are not supported by NCache LINQ Provider.
Note

Runtime indexing is not supported in NCache LINQ integration now.

To provide LINQ benefits, LINQ is integrated with NCache by implementing a class named NCacheQuery, which further implements the interface called IQueryable provided by .NET framework. This integration allows the user to run LINQ queries on cached items. For executing LINQ queries on cached items, an object implementing IQueryable interface should be defined and passed as an instance of cache which contains the object as shown below:

IQueryable<Product> products = new NCacheQuery<Product>(cache);

Defining Indexes

NCache requires all searchable attributes to be indexed. NCache provides its own indexing mechanism through which the users can identify objects in .NET assemblies that they want to index. See the section Indexing for details.

In This Section

Using LINQ in NCache
Explains how to use LINQ query based on NCache Query Language.

Configuring LINQPad for NCache
Provides steps to configure LINQPad to query over NCache data seamlessly.

Querying NCache Data in LINQPad
Explains how objects in NCache can be queried over using LINQPad.

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