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 regarding asymmetric key encryption are true？（）

• A、The same key is used for encryption and decryption.
• B、It is commonly used to create digital certificate signatures.
• C、It uses two keys： one for encryption and a different key for decryption.
• D、An attacker can decrypt data if the attacker captures the key used for encryption

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.

第3题：

第4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5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6题：

Which two statements are true about the primary key constraint in a table？ （）

• A、It is not possible to disable the primary key constraint.
• B、It is possible to have more than one primary key constraint in a single table.
• C、The primary key constraint can be referred by only one foreign key constraint.
• D、The primary key constraint can be imposed by combining more than one column.
• E、The non-deferrable primary key constraint creates an unique index on the primary key column if it is not already indexed.

第7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8题：

Which two statements regarding symmetric key encryption are true?（） (Choose two.)

• A、The same key is used for encryption and decryption.
• B、It is commonly used to create digital certificate signatures.
• C、It uses two keys: one for encryption and a different key for decryption.
• D、An attacker can decrypt data if the attacker captures the key used for encryption.

第9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10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