How can one query the blockchain's database?

Question

I realize that LMDB is very different from your typical SQL database, but is there a query language, or scripting language interface, that can be used to query the blockchain's database?

I am aware of this question on displaying the output histogram via a feature of monerod. Although, when trying that my daemon crashed. I would like to do something similar from a script.

Answer 1

If you're using python, the py-lmdb module includes a basic CLI. http://lmdb.readthedocs.io/en/release/

Keep in mind that you'll be getting raw data back, not anything in a human-readable format.

Answer 2

I don't think there is an equivalent of the mysql or psql commands for lmdb, therefore to make custom queries to the database you must write a program that accesses it directly.

There are some examples at github.com/moneroexamples:

• github.com/moneroexamples/lmdbcpp-monero
• github.com/moneroexamples/access-blockchain-in-cpp
• github.com/moneroexamples/finding-mine-tx-ins-and-outs
• github.com/moneroexamples/transactions-export