0004 - Proof of Item Listing Match¶

Description¶

Once GNAWEX finds one or more listings to match with the listing just created, it has to generate one or more proofs that the listings were indeed matched. This is the job for the Item Listing Transaction. The listing transaction(s) must start off as PENDING for the parties involved to execute the exchange in MouseHunt.

If the completed transactions add up to any of the involved listings' quantity, then only the affected listings must be automatically delisted as it has nothing else to exchange.

In the following diagram, we'll assume that all listings:

are of item CRM; and
cost the same SB

graph LR
  LIST_ONE[/User: Larry<br/>Quantity: 25<br/>Batch: 4<br/>Type: Sell/] --> TXN_ONE[Transact#1<br/><br/>Quantity: 2];
  LIST_TWO[/User: Bob<br/>Quantity: 2<br/>Batch: 4<br/>Type: Buy/] --> TXN_ONE;
  TXN_ONE --> LIST_ONE_A[/User: Larry<br/>Quantity: 23<br/>Batch: 4<br/>Type: Sell/]
  TXN_ONE --> LIST_TWO_A[/User: Bob<br/>Quantity: 0<br/>Batch: 4<br/>Type: Buy/]

  LIST_ONE_A --> TXN_TWO[Transact#2<br/><br/>Quantity: 22]
  LIST_THREE[/User: Steve<br/>Quantity: 22<br/>Batch: 4<br/>Type: Buy/] --> TXN_TWO
  TXN_TWO --> LIST_ONE_B[/User: Larry<br/>Quantity: 1<br/>Batch: 4<br/>Type: Sell/]
  TXN_TWO --> LIST_THREE_B[/User: Steve<br/>Quantity: 0<br/>Batch: 4<br/>Type: Buy/]

New listings must not be created as a result of the transaction output. Rather, this is just to show that provided with the transactions, we're able to determine what the final quantity is for the item listing. A copy of the quantity column will be created initally, and will be updated as transactions happen.

Operations¶

Create pending: all transactions created must be PENDING first because GNAWEX does not execute the actual exchange in MouseHunt
Cancel: if both parties mutually agree to terminate the exchange
Complete: if both parties have performed the exchange in MouseHunt

Permissions¶

Role	Cancel TXN	Complete TXN
System
Admin
Moderator
User	¹	¹
Guest (non-logged in user)

Database¶

Tables¶

`app.tradable_item_transactions`¶

Column name	Description	Type	Required	Nullable	Default
`id`	To uniquely identify an item transaction	`BIGINT GENERATED ALWAYS AS IDENTITY`	`true`	`false`	Supplied by Postgres
`buy_item_listing_id`	To associate a transaction to a buy listing	`BIGINT`	`true`	`false`	-
`sell_item_listing_id`	To associate a transaction to a sell listing	`BIGINT`	`true`	`false`	-
`status`	What the status is of the transaction	`app.TRANSACTION_STATUS AS ENUM ('PENDING', 'COMPLETED', 'CANCELLED')`	`true`	`false`	`PENDING`
`buyer_agreed`	If the buyer agreed to the new status	`BOOLEAN`	`true`	`false`	`false`
`seller_agreed`	If the seller agreed to the new status	`BOOLEAN`	`true`	`false`	`false`
`created_at`	To record when this was created	`TIMESTAMP WITH TIME ZONE`	`true`	`false`	`now()`
`updated_at`	To record when this was updated	`TIMESTAMP WITH TIME ZONE`	`false`	`true`	`now()` (if updated, otherwise `null`)
`quantity`	Initial number of units that the user wants to sell/buy	`INT`	`true`	`false`	-
`current_quantity`	Available number of units left	`INT`	`true`	`false`	`quantity`

Only for transactions they're involved in as the seller/buyer ↩↩