qortal/NOTES.md

General

• Reduce Qora2 down to core blockchain node with RESTful API access. Other libraries can process name-storage data into websites, or provide web-based wallet UI, etc.

• Trying to reduce number of external dependencies where possible, e.g. avoiding heavy-weight ORM like Hive, Hibernate, etc.

• Trying to reduce duplicated code, especially across transactions with lots of serialisation and signature generation.

• Transaction signatures should really be generated after creating the transaction, compared to the old style of generating signature first (and throw-away transaction in the process) then using signature when creating actual transaction!

• Trying to keep most of the source structure, naming, code paths, etc. similar to old Qora to reduce brain load!

• More comments/javadoc

• More JUnit tests

Differences due to switching from MapDB to HSQLDB

• We might need to maintain more mappings in the database, e.g. Qora address to/from public key, as previously public key objects could be stored directly in MapDB.

• The new database tried to store the data in "rawest" form, i.e. raw byte[] signatures, not base58-encoded.

• The Transactions table contains creator column, which duplicates various child table columns, e.g. PaymentTransactions.sender, so that all transactions by a specific Qora account can be quickly found without scanning all child tables.

• Trying to keep all SQL inside respective Java classes, e.g. operations on Blocks table only done within Block.java.

• Some MapDB-based objects had Java Map<> obejcts as their values. These will need to be unpicked into separate tables.

Possible gen2 refactoring already

• We might need to change Blocks.generator from Qora address in VARCHAR to public key in VARBINARY, then derive address from public key as needed.

• Ditto Transactions.creator and equivalent columns in child tables.

• Extracting values from a ResultSet by column index is efficient but prone to mistakes as the indexes have to be maintained by a human. There might be a better, general solution to this without having to resort to importing an external ORM library. Maybe simply value = resultSet.getInt(columnIndex++)