My .bitmonero/lmdb/data.mdb takes up too much space on my computer, and I'd like to delete it. If I do that, will it cause problems accessing my wallet?
data.mdb will not delete your wallet. The
data.mdb file is the blockchain. Deleting it does not affect your wallet.
Your wallet has a name of its own. You'll know what it is because it has at least one sister file that holds its keys. In other words, you'll know what "your_wallet" is because you'll see
your_wallet.keys (and maybe
A blockchain and its daemon are needed to be able to update your wallet and send funds. If you delete the blockchain, it implies you're happy sacrificing some level of privacy in favor of saving the space and related minor benefits. The privacy sacrifice is because you'll be forced to use a remote node. There are other posts on the Stack Exchange that explain the implications of using a remote node over your own node.