Is it safe to modify CCK tables by hand?

I'm not intimately familiar with CCK but I have a one-time custom setup and know that I could get some per开发者_JAVA技巧formance gains if I created indexes and changed the field type and length of some of the fields in my CCK table. Is it save to modify this table at all or will I end up destroying something in the process?

Thanks

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It depends on which type changes you want to do.

But unless you do anything crazy you should be alright. Your only problem would be that the forms and database doesn't match anymore, so CCK might allow more/less chars than your database, which could lead to some problems.