Which is better approach for encrypt and decrypt data?

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http://serverfault.com – i want to encrypt the data. still i am following to do this on ASP.NET Pages. i came to know that we can apply encryption/decryption on data at Backend means on SQL SERVER. I want to know which is the better way. Will i change it to on SQL SERVER or will go with as it is? I have studied This link to study which say only required columns should be encrypt/decrypt, not whole database. So please let me know which is better way from both of them. Still i am using AES to encrypt/decrypt data using C# (HowTos)