Finding a transaction in the blockchain I wanna understand how can a user find a certain transaction he created on the blockchain without him knowing on which block it belongs ? does he have to go over all the blocks using bloom filters to find his transaction ? narrow the search to an interval of timestamps ? there must be a special mechanism ...

I searched on google but all i found were websites to find them for u, i want to understand the actual mechanism used in the bitcoin protocol?

Block Explorers seems to be storing those transactions in special databases and they use their own approach to find transactions ... My question is about how full nodes find those transactions ? do they go over the whole chain trying to find them ?
After searching about this, i found out that each full node maintains a database with the set of unspent transaction outputs (UTXOs) in the memory. So When a new transaction is added, its UTXOs get updated accordingly (source). Also, a full node keeps track of all transactions that ever happened (source) and offer this:

Filtering transactions and blocks on behalf of lightweight nodes so that lightweight nodes do not need to download every transaction ever made on the network in order to find their own transactions.
Serving historical full blocks to nodes that have been offline for a while.
Transmitting new transactions from users to miners.
Broadcasting new blocks from miners to other nodes.

The RPC used for this call getrawtransaction that takes as an argument a TxID which is hashing twice the transaction data and gives you back the transaction you are searching for.