NEWID SQL Server

SQL Server > Built-In Functions > NEWID

Creates a unique value of type uniqueidentifier.

Example

DECLARE @myid uniqueidentifier
SET @myid = NEWID()

update
 user
set
 app_token = @myid
where
 id = 1

SET ANSI_NULLS SQL Server

Specifies ISO compliant behavior of the Equals (=) and Not Equal To (<>) comparison operators when they are used with null values.

SET ANSI_NULLS { ON | OFF }

When SET ANSI_NULLS is ON, a SELECT statement that uses WHERE column_name = NULL returns zero rows even if there are null values in column_name.

When SET ANSI_NULLS is OFF, the Equals (=) comparison operators do not follow the ISO standard. A SELECT statement that uses WHERE column_name = NULL returns the rows that have null values in column_name.

How to add HyperLink Column to Telerik RadGrid Code Behind

Telerik > RadGrid > GridHyperLinkColumn

Each row in a Hyperlink column will contain a predefined hyperlink. This link is not the same for the whole column and can be defined for each row individually.

DataNavigateUrlFields: Gets or sets a string, representing a comma-separated enumeration of DataFields from the data source, which will form the url of the windwow/frame that the hyperlink will target.

DataNavigateUrlFormatString: Gets or sets a string, representing a comma-separated enumeration of DataFields from the data source, which will form the url of the windwow/frame that the hyperlink will target.

Example:
Add hyperlink column to RadGrid programmatically

RadGrid grd = new RadGrid();

GridHyperLinkColumn linkColumn = new GridHyperLinkColumn();
string[] fld = { "id" };
linkColumn.DataNavigateUrlFields = fld;
linkColumn.DataNavigateUrlFormatString = "Default.aspx?ID={0}";
linkColumn.HeaderText = "Id";
grd.Columns.Add(linkColumn);

DataTable.Select Method (String) c#

C# > Data   > DataTable > Select

DataTable Select method gets an array of all DataRow objects that match the filter criteria.
If the column on the filter contains a null value, it will not be part of the result.

Example:

private void FilterDataTable(string filter)
{
    DataTable table = DataSet1.Tables["Person"];
    DataRow[] foundRows;

    // Use the Select method to find all rows matching the filter. Sample: filter = "name = 'dan' "
    foundRows = table.Select(expression);
    for(int i = 0; i < foundRows.Length; i ++)
    {
        Console.WriteLine(foundRows[i][0] );
    }
}

How to exit for C#

C# > Statements > break

How to exit for C#? The answer is break.
The break statement terminates the closest enclosing loop or switch statement in which it appears. Control is passed to the statement that follows the terminated statement.

Example:

for (int j = 0; j < list.Count; j++)
{
    if (j==5)
       break;
}

Transaction SQL Server

SQL Server

BEGIN TRANSACTION

BEGIN TRANSACTION represents a point at which the data referenced by a connection is logically and physically consistent. If errors are encountered, all data modifications made after the BEGIN TRANSACTION can be rolled back to return the data to this known state of consistency. Each transaction lasts until either it completes without errors and COMMIT TRANSACTION is issued to make the modifications a permanent part of the database, or errors are encountered and all modifications are erased with a ROLLBACK TRANSACTION statement.

ROLLBACK TRANSACTION

Rolls back an explicit or implicit transaction to the beginning of the transaction, or to a savepoint inside the transaction. You can use ROLLBACK TRANSACTION to erase all data modifications made from the start of the transaction or to a savepoint. It also frees resources held by the transaction.

COMMIT TRANSACTION

Marks the end of a successful implicit or explicit transaction. If @@TRANCOUNT is 1, COMMIT TRANSACTION makes all data modifications performed since the start of the transaction a permanent part of the database, frees the resources held by the transaction, and decrements @@TRANCOUNT to 0. If @@TRANCOUNT is greater than 1, COMMIT TRANSACTION decrements @@TRANCOUNT only by 1 and the transaction stays active.






Example

begin transaction

update table1
set field1='a'

if @@ERROR <> 0
begin
 rollback transaction
 RAISERROR ('Error table1',16,1)
 return -1
end


update table2
set field3='a'

if @@ERROR <> 0
begin
rollback transaction
RAISERROR ('Error table2',16,1)
return -1
end

commit transaction

Max upload file size in ASP.NET

ASP.NET > MaxRequestLength

The MaxRequestLength property specifies the limit for the buffering threshold of the input stream. For example, this limit can be used to prevent denial of service attacks that are caused by users who post large files to the server.

The default value is 4096 KB (4 MB).

Example: Set max size up to 64 MB in web.config

<httpRuntime
maxRequestLength="65536"
/>