1z0-883
单选题Consider the following: Which statement best describes the meaning of the value for the key_len column?（）AIt shows the total size of the index rowBIt shows how many columns in the index are examinedCIt shows the number of characters indexed in the keyD
题目
It shows the total size of the index row
It shows how many columns in the index are examined
It shows the number of characters indexed in the key
It shows how many bytes will be used from each index row
相似问题和答案
第1题：
A.It shows the total size of the index row
B.It shows how many columns in the index are examined
C.It shows the number of characters indexed in the key
D.It shows how many bytes will be used from each index row
第2题：
Of the two types of sentence stress, sense stress shows contrast, while logical stress shows meaning.（）
正确答案:错误
第3题：
To the author, the best thing that shows how a man is full of contradictions is the matter of sleep.()
第4题：
Which statement describes the effect on an index， when the indexed column for the rows is updatedin the base table（）
- A、An update in a leaf row takes place.
- B、The index becomes invalid after the update.
- C、The leaf block containing the row to be updated is marked as invalid.
- D、A row in the leaf block of the index for the key value is logically deleted and a new leaf row is inserted
正确答案:D
第5题：
Which two statements are true about constraints? （）
- A、The UNIQUE constraint does not permit a null value for the column.
- B、A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
- C、The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
- D、The NOT NULL constraint ensures that null values are not permitted for the column.
正确答案:B,D
第6题：
第7题：
The Device Manager in Windows XP shows that an incompatible device driver is installed. Which of the following BEST describes the icon that is displaying next to that device?（）
- A、Yellow question mark next to device
- B、Black checkmark next to device
- C、Yellow exclamation point next to device
- D、Red X next to the device
正确答案:C
第8题：
A. The indexed column is declared as NOT NULL.
B. The indexed columns are used in the FROM clause.
C. The indexed columns are part of an expression.
D. The indexed column contains a wide range of values.
第9题：
Which two statements are true about a bitmap index？ （）
- A、It is recommended for the columns that have unique values.
- B、It can be converted to a B-tree index by using the ALTER INDEX command.
- C、It has a bitmap segment for each distinct value in the key column， containing a string of bits in which each bit represents the presence or absence of a key column value.
- D、Updating the key column locks the whole bitmap segment that contains the bit for the key value to be updated.
正确答案:C,D
第10题：
When tuning Automatic PGA Memory Management， which of the following views will provide the information specified？（）
- A、 The V$PGA_TARGET_ADVICE view shows the predicted cache hit-ratio improvement if you increase PGA_AGGREGATE_TARGET
- B、 The V$PGA_TARGET_ADVICE view shows how the V$SQL_WORKAREA histogram will change if you change the value of PGA_AGGREGATE_TARGET
- C、 The V$PGA_TARGET_ADVICE_HISTOGRAM view shows how the V$SQL_WORKAREA_HISTOGRAM will change if you switch between Manual and Automatic PGA Memory Management
- D、 The V$PGA_TARGET_ADVICE view shows how performance will improve for the different work areas if you switch from Manual to Automatic PGA Memory Management
正确答案:A