storing chat data in txt file?

[sahil]

I am trying to create a chat function for my website and I just wanted to know whether it's a good idea to store the history in a txt file. I wanted to know wheater it would create extra load on the server and if there are any other means of storing data for storing chat data please do suggest them also I tried to store data in mysql directly, what I was doing (on localhost) was creating different tables for storing chats in the Tables, for example if user1 texts user2 the Table would be user1:user2 and then the rest of the chat would be a database entry. Any help would be really appreciated. If there are any disadvantages of storing chat data in txt form could you please write that down as well? Thanks a lot.