There are many events on ethereum smart contracts.
I want to mapping the events for indexing and querying.
But too hard to mapping because of large amounts of events.
Are there any event mapping tools or library to make it easy or automatically?
From your question, I imagine what you need is a Subgraph.
A Subgraph is a “set of instructions” containing
What on-chain triggers to listen for (the events from your contract)
The data you wish to query
The mapping between the two.
For your first subgraph, I recommend this workshop/tutorial GitHub - Web3Slimchance/zora-nft-workshop: Zora NFT Workshop
You can also check this section of the docs > Create a Subgraph - The Graph Docs