Caching Options for EF Core Caching Provider

Using EF Core Caching Provider allows you to use some integral caching features provided by NCache. These caching options are encapsulated in the CachingOptions class provided by the EF Core Caching Provider itself. These caching options are used to populate the cache item before inserting it into cache. The CachingOptions class contains the following methods and properties:

To utilize the CachingOptions API, include the following namespaces in your application:

  • Alachisoft.NCache.EntityFrameworkCore
  • Alachisoft.NCache.Runtime.Caching
Method Description
SetAbsoluteExpiration Specifies DateTime interval for Absolute Expiration. This sets the value for the read-only AbsoluteExpirationTime property.
SetSlidingExpirationTime Specifies TimeSpan interval for Sliding Expiration. This sets the value for the read-only SlidingExpirationTime property.

Property Description DefaultValue
AbsoluteExpirationTime Specifies time interval for Absolute Expiration. Can be set using the SetAbsoluteExpiration method. DefaultAbsolute
SlidingExpirationTime Specifies time interval for Sliding Expiration. Can be set using the SetSlidingExpiration method. DefaultSliding
ExpirationType Read-only enum to specify which expiration type has been configured for the cache item. The enum value is updated when expiration type is set using either SetAbsoluteExpiration() or SetSlidingExpiration(). The values for this enum are:
  • Absolute = 0
  • Sliding =1
    		•  Absolute
    QueryIdentifier Identifier for a query which is added as a Tag against the result set of the query in the cache. This MUST be unique for each unique query. QueryIdentifier is used to regenerate the result set from the cache upon execution of the same query again. The user must maintain a mapping of the query against the query identifier to be used in the future. If not specified, NCache adds the query string itself as the tag (making it unique for each unique query). For example, a query which returns a Customer is not tagged by the user. The next time the same query is executed, the query string is searched as a tag within the cache and if it exists, the result set against it will be returned. null
    StoreAs Enum that specifies how the entities should be added to the cache.
  • SeperateEntities = 0
    Items are added as separate entities.
  • Collection = 1
    Items are added as a List of entity type, for example, List<Customer>. Queries stored as collection do not share their data. As a result, overlapping entities will be stored again in cache when they are made part of another query.
    		•  Collection
    Priority Enum to specify the priority level for eviction of each cache item.
  • Low
  • BelowNormal
  • Normal
  • AboveNormal
  • High
  • Default
  • NotRemovable
    		•  Default
    CreateDbDependency Specifies whether a database dependency should be created for the cache item or not. If specified, the database type is specified through NCacheConfiguration.Configure() in the DbContext. false

    Example

    The following sample shows how caches can be configured according to the aforementioned parameters:

    CachingOptions options = new CachingOptions
{
    QueryIdentifier = new Tag("CustomerEntity"),
    CreateDbDependency = true,
    StoreAs = StoreAs.SeperateEntities,
    Priority = Runtime.CacheItemPriority.High
};

options.SetAbsoluteExpiration(new DateTime(2017, 6, 10));