多项选择题
A.committing a transaction
B.flashing back a transaction
C.recovering a failed transaction
D.running a read-consistent query
E.changing a tablespace status from READ ONLY to READ WRITE
多项选择题 Whichtwostatementscorrectlydescribetherelationbetweenadatafileandthelogicaldatabasestructures（）
单项选择题 ote the following structures in your database server： 1：Extents 2：OS Blocks 3：Tablespace 4：Segments 5：Oracle Data Block Which option has the correct arrangement of these structures from the smallest to the largest（）
单项选择题 Identifythelogicalstructurethatwillneverhavemorethanonedatasegmentcreatedforit.（）