Suppose you are only talking about a single currency pair, say EUR/USD. Throughout some period of time, you engage in trades with various other parties, sometimes buying, sometimes selling. The rates will be different for each trade, as the rates change in response to market conditions.
An example sequence of trades might look like this:
Time | Amount | Rate | t1 100 1.2636 t2 -1000 1.2599 t3 200 1.1612
and so on.
Later on, for a given current rate (say the market midpoint), you could transform all of these previous trades into a profit or loss as implied by that current rate. And you could summarize the whole sequence of trades with a "PnL" number by summing across the profit implied by each trade.
But what is usually meant by "position" after a sequence of such trades?
Does that term just refer to the running sum of the Amount column in my example (so just the pure number of units of the currency pair you've net bought/sold)?
The reason this puzzles me is that the position would lose information about what rate each amount was originally traded for. So, while the sum of the amounts would tell you your current total amount held (net long or net short), you wouldn't be able to work out profit from just snapshot of this total plus a snapshot of the rate.
Of course, this number could be useful for other purposes, like comparing how much relative exposure you have to one currency pair compared with another, outside of the running profit/loss of the trades that got you there.
Is this the correct way to think of "position" (e.g. it's just the running total amount you have net bought/sold, even if that summary number is useless in obtaining the profit at a point in time)?
Or is there something else that's customary for keeping track of position that also combines it with the rate at each trade?