Daily WYSIWYG record (2)

Sqlserver
When a where clause exists, SQL queries from the right to the left, such as: Select * from employee where sex = 'M' and age> 100 compared to select * from employee

Where age> 100 and sex = 'M'
High execution efficiency in SQL: exists in join
Insert the query result table into the table as a whole:
1. Select... into temptable
2. insert into... select

In Javascript
Make the HTML control not display: style. Display = "NONE" otherwise = "Block"
Keyboard action trigger event: onkeyup onkeydown onkeypress
You can use window. Reload (true) to refresh the page)
The array in Javascript starts from 1.
When the verification control and JavaScript are mixed, the verification control is invalid.
Recognize Web controls: form1.all ["_"]. valve, where _ is the control name
Sometimes you can manually execute the server first and then execute the client.

C #
In the itemdatabind event of the DataGrid, E. Item. itemtype = listitemtype. header contains the DataGrid header and selectitem.
It is best to set the type size when a value (output) is input and output in the stored procedure. For example, para [0] = new sqlparameter ("@ mediid", system. Data. sqldbtype. varchar, 6); 6 is the size
There are two ways to redirect a page:
1. Use server method: Server. Transfer ("webform. aspx ");
2. Use the browser method: Response. Redirect ("webform. aspx ");
Browser method: low performance, But browser Record Update
Disadvantages of the server method: the user's browser does not know that the page is transmitted, so it does not update the browser record. An error occurs when the page is refreshed (when the second page is turned over, the address
The address on the first page is displayed. When you click webcontrol, the address bar will be updated. Click htmlcontrol, and the address bar will not be updated)
Hash Table: (also called a hash table) is a data structure that is directly accessed based on the key code value. That is, it is accessed by ing the key code value to a location in the list.
Record to accelerate the search speed. This ing function is called the hash function, and the array storing records is called the hash list.
You can define Program Portal, for example:
If ()
{
If ()
{
If ()
{
If ()
{
}
}
}
}
It can be changed:
Bool flag = true;
If (flag = ture)
{}
If (flag = ture)
{}
If (flag = ture)
{}
If (flag = ture)
{}
B/S: do not place too many controls on the page; otherwise, ie will overflow.
Session occupies client memory, which is highly secure
Web control information is recorded in viewstate
An interface is a class with no attribute but Operation
The paging function in the DataGrid Control: in fact, the DataGrid Control obtains the number of pages that the User specifies to display in the pageindexchanged event, and then re-databind () data to display the specified page to form the page effect.

Windows
Run Group Policy Editor: gpedit. MSC
System Restoration: Win + r sfc/scannow