Key Fields

Streams store at most one record for each unique key. That is, the values in the key field or fields must be unique within the stream.

The following records each have unique keys:

[ Market = 'NYSE'; Symbol='T'; | Shares=10; Price=22.88; ]
[ Market = 'NYSE'; Symbol='GM'; | Shares=5; Price=16.81; ]

This third record matches the first record:

[ Market = 'NYSE'; Symbol='T'; | Shares=10; Price=20.15; ]

You cannot store both inside a stream, although you can overwrite the first record with this one with an update.