Monday, March 21, 2011

How to find out common element(s) in two generic list by LINQ, LINQ Set Operations

int[] twos = { 2, 4, 6, 8, 10 };
int[] threes = { 3, 6, 9, 12, 15 };

// 6
var intersection = twos.Intersect(threes);

// 2, 4, 8, 10
var except = twos.Except(threes);

// 2, 4, 7, 8, 10, 3, 9, 12, 15
var union = twos.Union(threes);

Understand SQL Injection by code

If put the following string in the SSN text box
' ; DROP DATABASE pubs  --
Using the input, the application executes the following stored procedure, which internally executes a similar SQL statement.
SqlDataAdapter myCommand = new SqlDataAdapter(
                                "LoginStoredProcedure '" +
                                 SSN.Text + "'", myConnection);

The code INJECT into the user's malicious input and generates the following query.
SELECT au_lname, au_fname FROM authors WHERE au_id = ''; DROP DATABASE pubs --'
 
Reference: 
How To: Protect From SQL Injection in ASP.NET