Function:
UseSQLCache dependency Technology,Can be implemented when the applicationProgramWhen the data in the corresponding database in
To clear the corresponding cache in the application.,Maximize program performance.
Implementation Method:
I,Create a database
A)The database cannot be dynamically attached.
B)Enable message transmission in the database
Alter database cachedependencytest set enable_broker
"Cachedependencytest" is the database created for you.
II,Used in applicationsSQLCache dependency Technology
A)CreateGlobal. asaxFile, add the following in the "application_start" methodCode:
// Start the SQL cache dependency listener when the program is running
String connstring = configurationmanager. connectionstrings ["cachedependencytestconnectionstring"]. connectionstring;
Sqldependency. Start (connstring );
B)Use cache dependency on the page to use the cache
Protected void page_load (Object sender, eventargs E)
{
// The SELECT statement must contain the exact column name, and the table name must also contain the user name,
// For example, DBO in the following DBO. cachetable table cannot be omitted
String SQL = "select username from DBO. cachetable ";
String connstring = configurationmanager
. Connectionstrings ["cachedependencytestconnectionstring"]
. Connectionstring;
Sqlconnection conn = new sqlconnection (connstring );
Sqldataadapter da = new sqldataadapter (SQL, Conn );
Datatable dt = new datatable ();
// Create an SQL cache dependency. Use a selectcommand as the parameter.
System. Web. caching. sqlcachedependency denpendency
= New system. Web. caching. sqlcachedependency (DA. selectcommand );
// Fill in the data in the database to DT. You can fill in the data only after creating the cache dependency.
Da. Fill (DT );
// If the table dt is not in the cache, add the table DT to the cache.
If (Cache ["cachetable"] = NULL ){
Cache. insert (
"Cachetable" // cache name
, DT // the object to be cached. Here is a datatable
, Denpendency // SQL cache dependent object
// Cache expiration time, which is set to never expire.
// The cache will not be cleared until the table data in the database is changed
, System. Web. caching. cache. noabsoluteexpiration
// Set the sliding time to 0;
// If it is set to 5, it indicates that if you do not send a request within 5 seconds, it will be cleared from the cache
, Timespan. Zero
);
// Used for testing, so that you can know whether the data is read from the cache on the interface.
This. lblflag. Text = "out of cache" + datetime. Now. tostring ();
}
Else
{
This. lblflag. Text = "use cache" + datetime. Now. tostring ();
}
// Read data from the cache
This. gridview1.datasource = cache ["cachetable"] As datatable;
This. gridview1.databind ();
}
C)Page code:
<% @ Page Language = "C #" autoeventwireup = "true" codebehind = "appcache. aspx. cs" inherits = "cachetest. appcache" %>
<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<HTML xmlns = "http://www.w3.org/1999/xhtml">
<Head runat = "server">
<Title> </title>
</Head>
<Body>
<Form ID = "form1" runat = "server">
<Div>
<Asp: Label id = "lblflag" runat = "server"> </ASP: Label>
<Asp: gridview id = "gridview1" runat = "server">
</ASP: gridview>
</Div>
</Form>
</Body>
</Html>
Address: http://www.cnblogs.com/seerlin/archive/2008/12/19/1358128.html
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