多选题The InnoDB engine has a feature known as clustered indexes. Which three statements are true about clustered indexes as used in InnoDB?（）AA primary key must exist for creation of a clustered indexBA clustered index allows fulltext searching within InnoD
题目
多选题
The InnoDB engine has a feature known as clustered indexes. Which three statements are true about clustered indexes as used in InnoDB?（）
A
A primary key must exist for creation of a clustered index
B
A clustered index allows fulltext searching within InnoDB
C
The first unique index is always used as a clustered index and not a primary key
D
A clustered index provides direct access to a page containing row data
E
If no indexes exist, a hidden clustered index is generated based on row IDs
F
A primary key is used as a clustered index
G
A clustered index is a grouping of indexes from different tables into a global index for faster searching