The idx column was described as the trade's position within its slot, numbered separately for landed and failed rows. It is the transaction's 0-based position in its block (checked against the chain), shared by every table; (slot, idx) is the join key to signatures.
Card: the full archive's tables, joins, scale and licence
Adds what researchers asked after reading the sample: the other tables (events, signatures, holder balance changes, the completeness receipt), the (slot, idx) join, block time only, a month's size, and what the licence allows for the full files. No prices.
