多选题You need to replicate a table from a master to a slave. The master and slave copies of the table will have different number of columns. Which two conditions must be true?（）AEach extra column in the copy with more columns must not have a default valueBC
题目
多选题
You need to replicate a table from a master to a slave. The master and slave copies of the table will have different number of columns. Which two conditions must be true?（）
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