注意是一种（）。

In digital systems, the SNR is usually defined by, wheredenotes _____of AWGN.

A．A.user defined table function

B．B.user defined aggregation function

C．C.user defined scalar function

D．D.user defined function

A．user defined table function

B．user defined aggregation function

C．user defined scalar function

D．user defined function

A.Each extra column in the copy with more columns must not have a default value

B.Columns that are common to both versions of the table must be defined in the same order on the master and the slave

C.The slave database cannot have more columns than the master. Only the master database can have more columns

D.Columns that are common to both versions of the table must come first in the table definition, before any additional columns are additional columns are defined on either server

E.The master database cannot have more columns than the slave. Only the slave deatbase can have more columns