Which three statements are true about the interpretation of an execution plan?(Choose
three.)
A.
The cost of the entire plan is indicated by the line with Id 0 and always includes both I/O
and CPU resources.
B.
TheROWScolumn indicates the cardinality of each operation and is always calculated by
dividing the total number of rows in the table by the number of distinct values in the column
used in theWHEREclause predicate.
C.
ATABLE ACCESS FULLin theOperationcolumn for a query with aWHEREclause
occurs only if no index exists for the filter column.
D.
AnINDEX UNIQUE SCANin theOperationcolumn always implies that only one row will
be returned.
E.
AHASH JOINin theOperationcolumn always implies that two tables are joined by using
an equijoin.
A – right
B – wrong, because the cardinality can be calculated not only by dividing the total number of rows by the number of distinct values
C – wrong, because FTS can occur even the index exists on indexed column
D – right, index unique scan always returns one row
E – right, hash join is an equijoin
A,D,E
ADE
A,D,E