linking 2 tables

[fipp]

I have 2 tables in a database about a football game. The tables are 'game'
and 'play'. Naturally there is 1 game with many plays.

'game'
gameid
team
opponent
date

'play'
playid
gameid
down
distance
yardline
posessionteam
offenseplay
defenseplay
gain

when I create a query and link the 2 tables via gameid my query is not
editable. The reason I need to link them and edit it is because I am trying
to calculate a value and in the calculation I need to know when team is equal
to posessionteam.

 

[fipp]

it is working now. In the original game table gameid was not the primary key.