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 from the table causes a logical deletion in index leaf block and the space becomesavailable for the new leaf entry
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 from the table causes a logical deletion in index leaf block and the space becomesavailable for the new leaf entry
相关考题：
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 the keyD.It shows how many bytes will be used from each index row
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.
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
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.
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.
Which two statements are true regarding partitioning in Mysql?（）A、Tables with BLOB and TEXT columns cannot be partitionedB、Partitioning allows easier management of smaller data sets for certain queriesC、Partitioning allows different columns to be stored in separate filesD、The partitioning expression is an integer or function that returns an integer value or NULL valueE、Partitioning is only available for those storage engines that implements it natively
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.
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.
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
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
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
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
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.
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.
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.
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.
单选题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？（）AA leaf will be marked as invalid.BAn update in a leaf row takes place.CThe index will be updated automatically at commit.DA leaf row in the index will be deleted and inserted.EThe index becomes invalid when you make any updates
多选题What two statements are true regarding the recommendations received from the SQL Access Advisor?（）(Choose two.)AIt cannot generate recommendations that support multiple workload queries.BIt can recommend partitioning on tables provided that the workloads have some predicates and joins on the columns of the NUMBER or DATE type.CIt can recommend partitioning only on tables that have at least 10,000 rows.DIt can recommend only B-tree indexes and not bitmap or function-based indexes
多选题Which two statements regarding asymmetric key encryption are true？（）AThe same key is used for encryption and decryption.BIt is commonly used to create digital certificate signatures.CIt uses two keys： one for encryption and a different key for decryption.DAn attacker can decrypt data if the attacker captures the key used for encryption
单选题Which statement describes the effect on an index， when the indexed column for the rows is updatedin the base table（）AAn update in a leaf row takes place.BThe index becomes invalid after the update.CThe leaf block containing the row to be updated is marked as invalid.DA row in the leaf block of the index for the key value is logically deleted and a new leaf row is inserted
多选题What two statements are true regarding the recommendations received from the SQL Access Advisor？（）AIt cannot generate recommendations that support multiple workload queries.BIt can recommend partitioning on tables provided that the workloads have some predicates and joins on the columns of the NUMBER or DATE type.CIt can recommend partitioning only on tables that have at least 10，000 rows.DIt can recommend only B-tree indexes and not bitmap or function-based indexes.
单选题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？（）AAn update in a leaf row takes place.BThe index becomes invalid after the update.CThe leaf block containing the row to be updated is marked as invalid.DA row in the leaf block of the index for the key value is deleted and inserted.
多选题Which two statements are true about a bitmap index？ （）AIt is recommended for the columns that have unique values.BIt can be converted to a B-tree index by using the ALTER INDEX command.CIt 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.DUpdating the key column locks the whole bitmap segment that contains the bit for the key value to be updated.
多选题Which two statements are true regarding B-tree index（）AThe leaf blocks in the index are doubly linked.BThe leaf node stores a bitmap for each key value.CThe rows with NULL value in key columns also have entries in the index.DThe 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.
多选题Which two statements are true about constraints? （）AThe UNIQUE constraint does not permit a null value for the column.BA UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.CThe PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.DThe NOT NULL constraint ensures that null values are not permitted for the column.
多选题Which two statements regarding symmetric key encryption are true?（） (Choose two.)AThe same key is used for encryption and decryption.BIt is commonly used to create digital certificate signatures.CIt uses two keys: one for encryption and a different key for decryption.DAn attacker can decrypt data if the attacker captures the key used for encryption.
多选题Which two statements are true regarding B-tree indexs（）AThe leaf blocks in the index are doubly linked.BThe leaf node stores a bitmap for each key value.CThe rows with NULL value in key columns also have entries in the index.DThe deletion of a row from the table causes a logical deletion in index leaf block and the space becomesavailable for the new leaf entry