Which two statements are true regarding B-tree indexs（）A、The leaf blocks in the index are doubly linked.B、The leaf node stores a bitmap for each key value.C、The rows with NULL value in key columns also have entries in the index.D、The deletion of a row fro

第1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.

第2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.

第3题：

What two statements are true regarding the recommendations received from the SQL Access Advisor?（）(Choose two.)

• A、It cannot generate recommendations that support multiple workload queries.
• B、It can recommend partitioning on tables provided that the workloads have some predicates and joins on the columns of the NUMBER or DATE type.
• C、It can recommend partitioning only on tables that have at least 10,000 rows.
• D、It can recommend only B-tree indexes and not bitmap or function-based indexes

第4题：

Which statement is true regarding the COALESCE function?（）

• A、It can have a maximum of five expressions in a list 
• B、It returns the highest NOT NULL value in the list for all rows 
• C、It requires that all expressions in the list must be of the same data type 
• D、It requires that at least one of the expressions in the list must have a NOT NULL value

第5题：

Examine the command：   ALTER DATABASE ADD SUPPLEMENTAL LOG DATA （PRIMARY KEY） COLUMNS；   What does the command accomplish？（）

• A、Creates an additional copy of the database online redo log files. 
• B、Stores the primary key column values of each row involved in a DML operation in the online redo log files. 
• C、Stores the primary key column values of each row involved in a DML operation in the supplemental log files. 
• D、Stores the old and new primary key column values of each row involved in a DML operation only when the primary key is modified in the online redo log files.

第6题：

Which two statements are true regarding B-tree index（）

• A、The leaf blocks in the index are doubly linked.
• B、The leaf node stores a bitmap for each key value.
• C、The rows with NULL value in key columns also have entries in the index.
• D、The deletion of a row from the table causes a logical deletion in index leaf block and the space becomes available for the new leaf entry.

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第13题：

Which two statements are true regarding partitioning in Mysql?（）

• A、Tables with BLOB and TEXT columns cannot be partitioned
• B、Partitioning allows easier management of smaller data sets for certain queries
• C、Partitioning allows different columns to be stored in separate files
• D、The partitioning expression is an integer or function that returns an integer value or NULL value
• E、Partitioning is only available for those storage engines that implements it natively

第14题：

As a result of performance analysis， you created an index on the prod_name column of the prod_det table， which contains about ten thousand rows. Later， you updated a product name in the table. How does this change affect the index？（）

• A、A leaf will be marked as invalid.
• B、An update in a leaf row takes place.
• C、The index will be updated automatically at commit.
• D、A leaf row in the index will be deleted and inserted.
• E、The index becomes invalid when you make any updates.

第15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

第16题：

You work as a database administrator for Certkiller .com. As a result of performance analysis， you created an index on theprod_namecolumn of the  Certkiller prodtable， which contains about ten thousand rows. Later， you updated a product name in the table.  How does this change affect the index？（）

• A、A leaf will be marked as invalid.
• B、An update in a leaf row takes place.
• C、The index will be updated automatically at commit.
• D、A leaf row in the index will be deleted and inserted.
• E、The index becomes invalid when you make any updates

第17题：

The SCOTT user has an index on the ITEM_DESC column of the ITEM table. As part of the year-ending task， SCOTT updates the ITEM_DESC column for most of the rows in the ITEM table. How does this change to the table affect the index？（）

• 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 deleted and inserted.

第18题：

What two statements are true regarding the recommendations received from the SQL Access Advisor？（）

• A、 It cannot generate recommendations that support multiple workload queries.
• B、 It can recommend partitioning on tables provided that the workloads have some predicates and joins on the columns of the NUMBER or DATE type.
• C、 It can recommend partitioning only on tables that have at least 10，000 rows.
• D、 It can recommend only B-tree indexes and not bitmap or function-based indexes.

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