Microsoft Technology

Throw Vs Throw ex Posted: 29 Jun 2010 08:41 AM PDT Throw Throw Ex try    {         // do some operation that can fail    }    catch (Exception ex)    {         // do some local cleanup         throw;    } try    {         // do some operation that can fail    }    catch (Exception ex)    {         // do some local cleanup         throw ex;    } It preserve the Stack information with Exception It Won't Send Stack information with Exception This is called as "Rethrow" This is called as "Breaking the Stack" If want to throw new exception, throw new ApplicationException("operation failed!"); If want to throw new exception, throw new ApplicationException("operation failed!",ex);

Finalize Vs Dispose Posted: 29 Jun 2010 07:03 AM PDT Finalize Dispose Implicit way to destroy the object Explicit Way to Destroy Object It Cannot Override It Can be Override It freed up the memory used by the object only when scope of the expired Dispose is forcibly freed up the memory It is called by GC at runtime It is called by user If you call finalize, it will move to finalize queue, GC will finalize the object by freed up the memory It will directly freed up the memory It will be handling by GC, no inconsistent error occur Error will occur, because it is not controlled by GC

Functions (UDF) Vs Stored Procedures (SP) Posted: 29 Jun 2010 03:49 AM PDT Functions (UDF) Stored Procedures (SP) Execute Functions thru SQL Statement It Can not be used in SQL Statements UDF run thru SQL SELECT SP run thru EXECUTE OR EXEC You can't use DDL, DML statements in UDF It is possible in SP It always return values It May or May not return value UDF return single resultset SP can return multiple resultset Function can't return XML output SP can return XML output UDF can have only Input Parameter SP can have Input & Output Parameter SP can not call thru Functions Function can be called from SP Exception handling is not Possible Exception Handling is possible

Composite Key / Concatenated Key / Aggregate Key: Posted: 28 Jun 2010 10:38 PM PDT Composite Key is a primary key, combination of more than one column to maintain unique record. It is also known as Concatenated Key or Aggregate Key For example: CREATE TABLE InvoiceDetails (       InvoiceNo numeric(18,0),       itemNumber numeric(18,0),       productId  int,       quantity   numeric(18,2),       PRIMARY KEY (InvoiceNo, itemNumber)) InvoiceDetails table may have a composite key on InvoiceNo & itemNumber

Referential integrity Posted: 28 Jun 2010 10:10 PM PDT It is a Database concept, it maintain the consistent relation between parent and child tables. When one table contains FK, it may not allow inserting any values in key columns of the child tables which is not existed in parents table. It supports cascading update and cascading delete, which ensures the changes made to the child table will be reflected in parent table as well.

How to List All the Databases from SQL Server Posted: 28 Jun 2010 08:52 PM PDT You can use any of the following queries to retrieve list of all databases SELECT name FROM sys.databases SELECT name FROM sys.sysdatabases Or you can use the following system stored procedure EXEC sp_databases EXEC sp_helpdb