多项选择题

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