フリー問題

問題文

The key selection logic is to be changed so that a unique key admitting empty values is treated as a candidate for identifying a row. For which Replicat mode does the documentation rule that setting invalid, and what does it warn about the installations?

選択肢

1. Parallel mode, which the setting is not valid for, and every installation has to be brought into step because the setting bears on what goes into the trail
2. Coordinated mode, which the setting is not valid for, and every installation has to be brought into step because the setting bears on what goes into the trail
3. No mode at all, since the setting is valid for every one of them, and only the installation holding the target has to carry the setting because it bears on how rows are matched there
4. Integrated mode, which the setting is not valid for, and every installation has to be brought into step because the setting bears on what goes into the trail