can any body help me what is Data Model..? when do we use this..?

Can any body help me what is data binding , what are the types of data binding ,where we use data binding...? give me examples.

can any body help me What is the difference between Security Token and Verification Code..?

How can i schedule dataloader and what are the main drawbacks of dataloader.............?

Any body help me what are the main drawbacks of change sets..............?

can any body help me what is the characters limit of URL field....?

i need a validation rule that is working for only newly inserted record but not old records..? how can i achieve this scenario...

can any body help me how can i schedule a class to run every half an hour ...? and also every hour....? plz send me code..

can any body help me in which situations we are using custom report types.............?

can any body help me how can i cover addError() message of trigger in test clas..?

I want to execute schedule class per every one hour from developer console..? how can i run this class every one hour can any body help how can i achiee this...?

how many workflows and workflowapprovals i can create in once organization and how many workflows and workflowapprovals are activate..?

 how can i make trigger fires only once that is first time only . how can i do this..? can anybody help me...

What is Terrotory Management... why we use this,and where we use this and what is the main purpose of this....? in which cases we use this .. plz anybody help mee...?

what is public cloud..? and what is private cloud..? any body help me what is the difference between two clouds..?

Is it possible to prevent duplicates using dataloader ,if it is possible then how can we prevent duplicates using Dataloader.... Please help me any body...?

i have SAP application and its WSDL how can i integrate sap application into salesforce..........? any body please help me....................... and send me the process

Can any body help me can we deploye profiles from sandbox to production.....?

Can any body help me what REST API..? what is the main purpose of use this REST API in salesforce.? in which situation we use this REST API. Can any body send sample code of RESR API.?

I have displayed Account records in pageblock table , and account names are displayed in command link when ever i click on command link the detail page of that particular account will displayed below the pageblock table , that detail page contains related list, from that related list i want to delete child records without refreshing the whole page that means here i want partial page refresh. Can any body help me..?