difference between NDA and CDA agreement

My company is a sales and marketing company we have some important Data like client list, project details etc which is fully confidantial. We want to make non desclousure agreement with our employee, is it is leagal and can anybody guide how to do it, and is their any difference between NDA and CDA agreement

By CDA you mean Confidential Disclosure Agreement, it is also referred to as Non-Disclosure Agreement (NDA) also known as Secrecy Agreement. It is a legal agreement made between the organisation and an employee which states that the information the employee is shared has to be restricted from wider use.

Thank you for the reply is both agreements the same or is there some difference? Please advice

Yes, they are legal, though it is difficult to ensure compliance.
Number of formats are available on net.