Enterprise Library Caching and Sql Dependencies

ok so they didn't add the functionality for the sql dependencies and notifications into the enterprise library, so this is what i came up with so far as a wrapper:

public class SqlExpiration : Microsoft.Practices.EnterpriseLibrary.Caching.ICacheItemExpiration, IDisposable
        {
            private SqlCacheDependency dp = null;
            private string database = string.Empty;
            private string table = string.Empty;
            public SqlExpiration(string database, string table)
            {
                this.table = table;
                this.database = database;


                dp = new SqlCacheDependency(database, table);
            }


            #region ICacheItemExpiration Members


            public bool HasExpired()
            {
                return dp.HasChanged;
            }


            public void Initialize(Microsoft.Practices.EnterpriseLibrary.Caching.CacheItem owningCacheItem)
            {
            }


            public void Notify()
            {
            }


            #endregion


            #region IDisposable Members


            public void Dispose()
            {
                if (dp != null)
                {
                    dp.Dispose();
                }
            }


            #endregion
        }

am i missing anything? it seems to work fine i just have no idea

Re: Enterprise Library Caching and Sql Dependencies

Hi Harold.NET,

very interesting indead!!! I like using the EntLibrary Caching service in my custom Data Access Layer instead of the web cache (which all the examples and people say to use) because i feel like it's tightly binding http web stuff to a reusable component (assembly) that might not be doing any web stuff. Pedantic, i know ... but it's the principle, for me at least.

That said, i stumbled across this post and it has me VERY interested. I'm about to try this out ... but i was curious to see if you ended up using this in any projects? you said 'It seems to work fine' ... but can u elaborte on that - ie. The cache items get wiped/zapped when a database table gets updated -- proving that the sqlnotification broker stuff is working.

also, did u setup your stuff using the asp_regsql.exe command?

Please reply - very very intersted :)

oh, ps. your two database and name fields are redundant - not required.

Re: Enterprise Library Caching and Sql Dependencies

Yes, I used the reqsql command and all.

It is working great for my projects, I see no issues at all with anything.

Re: Enterprise Library Caching and Sql Dependencies

Hi Harrold.

1) Why did u use the aspnet_regsql.exe command? what functionality does it do, which you are required to use?

2) Why did u go with using the EntLibrary's Caching component instead of using the http caching stuff which most people suggest using? The reason i ask this is because I don't want to use the Asp caching object thing because i'm doing my caching in a Data Access Layer and it seems silly to put web stuff in there when the reusable assembly might not be doing any web stuff at all (eg a winform app) .. even though the System.Web... namespace stuff works fine in a winform ... and the SqlCacheDependency class is found in System.Web.... or something.

Re: Enterprise Library Caching and Sql Dependencies

Harold,

Have you used this in a farm/clustered environment? We ran across a problem with caching in sql server for a couple reasons. 1) I wasn't specifying an expiration so the artifacts remained in cache indefinitely and 2) when a server in the cluster reset, caching would blow chunks until a manual delete was issued for the tables that stored the cached artifacts.

-T