etymology - Which grammar rules are applied when でいい is conjugated to nouns?

"ここに名前を書くだけでいいですか？" means "Is it ok to just write [my] name here?"

I'm confused about where でいい comes from.

http://www.guidetojapanese.org/learn/grammar/must#part5 is about conjugating ていい /でいい to adjectives and verbs.

I don't know which grammar rules are applied when でいい is conjugated to nouns as in "ここに名前を書くだけでいいですか？".

Can anyone tell me?

Answer

The 「〜でいい」 you see after nouns can be analyzed as follows:

「だ」's continuative form + 「いい」

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「だ」's continuative form, 「で」, should not be confused with the 「…で」 you see in the て-form of verbs (like 「飲んで」), which is actually just a 「て」 that has undergone a sound change:

　 //nomite//
⇒ //nomte//
⇒ //nonde//