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
单选题
Consider the following: Which statement best describes the meaning of the value for the key_len column?（）
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

相似考题

1.To the author, the best thing that shows how a man is full of contradictions is the matter of sleep.()

2.Consider the following:Which statement best describes the meaning of the value for the key_len column?()A.It shows the total size of the index rowB.It shows how many columns in the index are examinedC.It shows the number of characters indexed in the keyD.It shows how many bytes will be used from each index row

3.Which of the following shows the proper rhythmical pattern of the sentence?

4.In which scenario would index be most useful? ()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.

更多“单选题Consider the following: Which statement best describes the meaning of the value for the key_len column?（）A It shows the total size of the index rowB It shows how many columns in the index are examinedC It shows the number of characters indexed in th”相关问题

  • 第1题：

    Of the two types of sentence stress, sense stress shows contrast, while logical stress shows meaning.（）


    正确答案:错误

  • 第2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3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4题：

    You are using Oracle Enterprise Manager to estimate the size of a table to be created. You have typed data regarding the column names， data types， sizes of the columns， and the projected number of rows in the table. Which additional information does the Oracle Enterprise Manager return？（）

    • A、 space allocated in the tablespace
    • B、 space required for the bitmap index on a column of the table
    • C、 space remaining in the tablespace after creating the table
    • D、 estimated value of the PCTFREE storage parameter

    正确答案:A

  • 第5题：

    In which scenario would index be most useful?（）

    • 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.

    正确答案:D

  • 第6题：

    单选题
    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： B
    解析： 暂无解析

  • 第7题：

    单选题
    In which scenario would index be most useful? （）
    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.


    正确答案： D
    解析： 暂无解析

  • 第8题：

    多选题
    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： D,A
    解析： 暂无解析

  • 第9题：

    多选题
    Examine the SQL statement that creates ORDERS table: CREATE TABLE orders (SER_NO NUMBER UNIQUE, ORDER_ID NUMBER, ORDER_DATE DATE NOT NULL, STATUS VARCHAR2(10) CHECK (status IN ('CREDIT', 'CASH')), PROD_ID NUMBER REFERENCES PRODUCTS(PRODUCT_ID), ORD_TOTAL NUMBER, PRIMARY KEY (order_id, order_date)); For which columns would an index be automatically created when you execute the above SQL statement? （）
    A

    SER_NO

    B

    ORDER_ID

    C

    STATUS

    D

    PROD_ID

    E

    ORD_TOTAL

    F

    composite index on ORDER_ID and ORDER_DATE


    正确答案： A,F
    解析： 暂无解析

  • 第10题：

    单选题
    Which of the following is the best way to combine sentences 9 and 10 (reproduced below)?Huge billboards advertise shows, shops, and mutts. Hotels, motels, and tour buses are everywhere.
    A

    The streets are lined with hotels, motels, tour buses, and huge billboards advertising shows, shops, and mails.

    B

    The streets are lined with hotels, motels, and tour buses whose occupants take in huge billboards that are everywhere advertising shows, shops, and malls.

    C

    Huge billboards surrounding hotels, motels, and tour buses, which are everywhere, advertise shows, shops, and mails.

    D

    Huge billboards advertise shows, shops, and malls and surround hotels, motels, and tour buses, which are everywhere.

    E

    The streets are lined: hotels, motels, and tour buses me everywhere, and their occupants take in huge billboards advertising shows, shops, and malls.


    正确答案： A
    解析：
    A项最好地将第9句和第10句的思想结合在一起，将“hotels, motels, and tour buses”放在广告牌前很合理。

  • 第11题：

    多选题
    Examine the SQL statement that creates ORDERS table: CREATE TABLE orders (SER_NO NUMBER UNIQUE, ORDER_ID NUMBER, ORDER_DATE DATE NOT NULL, STATUS VARCHAR2(10) CHECK (status IN ('CREDIT', 'CASH')), PROD_ID NUMBER REFERENCES PRODUCTS(PRODUCT_ID), ORD_TOTAL NUMBER, PRIMARY KEY (order_id, order_date)); For which columns would an index be automatically created when you execute the above SQL statement? （）
    A

    SER_NO

    B

    ORDER_ID

    C

    STATUS

    D

    PROD_ID

    E

    ORD_TOTAL

    F

    composite index on ORDER_ID and ORDER_DATE


    正确答案： F,C
    解析： 暂无解析

  • 第12题：

    单选题
    which one of the following best describes the use of hidden column formula?（）
    A

    views can be hidden based on a formula 

    B

    hidden columns are not a supported feature 

    C

    table columns can be hidden based on a formula  

    D

    view columns can be displayed or hidden based on a formula 


    正确答案： A
    解析： 暂无解析

  • 第13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14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15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

  • 第16题：

    Consider the following statement：   SQL> EXECUTE DBMS_STATS.GATHER_SHEMA_STATS （-  2> ownname => ‘OE’， -  3> estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE， -  4> method opt => ‘for all columns size AUTO’）；   What is the effect of ‘for all columns size AUTO’ of the METHOD_OPT option？（）

    • A、The Oracle server creates a new histogram based on existing histogram definitions for all table, column, and index statistics for the OE schema. 
    • B、The Oracle server creates a histogram based on data distribution regardless of how the application uses the column/s for all table, column, and index statistics for the OE schema.
    • C、The Oracle server creates a histogram based on data and application usage of the column/s for all table, column, and index statistics for the OE schema. 
    • D、The Oracle server creates a histogram based on application usage, regardless of data distribution, for all table, column, and index statistics for the OE schema.

    正确答案:C

  • 第17题：

    which one of the following best describes the use of hidden column formula?（）

    • A、views can be hidden based on a formula 
    • B、hidden columns are not a supported feature 
    • C、table columns can be hidden based on a formula  
    • D、view columns can be displayed or hidden based on a formula 

    正确答案:D

  • 第18题：

    单选题
    You are using Oracle Enterprise Manager to estimate the size of a table to be created. You have typed data regarding the column names， data types， sizes of the columns， and the projected number of rows in the table. Which additional information does the Oracle Enterprise Manager return？（）
    A

     space allocated in the tablespace

    B

     space required for the bitmap index on a column of the table

    C

     space remaining in the tablespace after creating the table

    D

     estimated value of the PCTFREE storage parameter


    正确答案： C
    解析： 暂无解析

  • 第19题：

    单选题
    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： A
    解析： 暂无解析

  • 第20题：

    多选题
    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： A,B
    解析： 暂无解析

  • 第21题：

    单选题
    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： B
    解析： 暂无解析

  • 第22题：

    单选题
    Consider the following statement：   SQL> EXECUTE DBMS_STATS.GATHER_SHEMA_STATS （-  2> ownname => ‘OE’， -  3> estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE， -  4> method opt => ‘for all columns size AUTO’）；   What is the effect of ‘for all columns size AUTO’ of the METHOD_OPT option？（）
    A

    The Oracle server creates a new histogram based on existing histogram definitions for all table, column, and index statistics for the OE schema. 

    B

    The Oracle server creates a histogram based on data distribution regardless of how the application uses the column/s for all table, column, and index statistics for the OE schema.

    C

    The Oracle server creates a histogram based on data and application usage of the column/s for all table, column, and index statistics for the OE schema. 

    D

    The Oracle server creates a histogram based on application usage, regardless of data distribution, for all table, column, and index statistics for the OE schema.


    正确答案： D
    解析： 暂无解析

  • 第23题：

    单选题
    A total of 250 students participate in five different school-sponsored clubs. The bar graph below shows the number of students who participate in each club. 40% of the members of Club A are in Club B. How many of the members in Club A are not in Club B?
    A

    28

    B

    32

    C

    42

    D

    48

    E

    52


    正确答案： E
    解析：
    40% of the students in Club A are in Club B. That means 60% of the students in Club A are not in Club B. Find 60% of 70. 0. 60×70 = 42 students in Club A are not in Club B.

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