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.
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.
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
The InnoDB engine has a feature known as clustered indexes.Which three statements are true about clustered indexes as used in InnoDB?() A.A primary key must exist for creation of a clustered indexB.A clustered index allows fulltext searching within InnoDBC.The first unique index is always used as a clustered index and not a primary keyD.A clustered index provides direct access to a page containing row dataE.If no indexes exist, a hidden clustered index is generated based on row IDsF.A primary key is used as a clustered indexG.A clustered index is a grouping of indexes from different tables into a global index for faster searching
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 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 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
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
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.
Why does performance degrade when many UPDATE， INSERT， or DELETE statements are issued on a tablethat has an associated Bitmap index（）A、The DML operations re-create the Bitmap index blocks.B、The Bitmap index is rebuilt automatically after a DML operation.C、The smallest amount of a bitmap that can be locked is a bitmap segment.D、Additional time is taken to remove NULL values from the Bitmap index after a DML operation.
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.
The InnoDB engine has a feature known as clustered indexes. Which three statements are true about clustered indexes as used in InnoDB?（）A、A primary key must exist for creation of a clustered indexB、A clustered index allows fulltext searching within InnoDBC、The first unique index is always used as a clustered index and not a primary keyD、A clustered index provides direct access to a page containing row dataE、If no indexes exist, a hidden clustered index is generated based on row IDsF、A primary key is used as a clustered indexG、A clustered index is a grouping of indexes from different tables into a global index for faster searching
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
单选题Why does performance degrade when many UPDATE， INSERT， or DELETE statements are issued on a tablethat has an associated Bitmap index（）AThe DML operations re-create the Bitmap index blocks.BThe Bitmap index is rebuilt automatically after a DML operation.CThe smallest amount of a bitmap that can be locked is a bitmap segment.DAdditional time is taken to remove NULL values from the Bitmap index after a DML operation.
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.
多选题The InnoDB engine has a feature known as clustered indexes. Which three statements are true about clustered indexes as used in InnoDB?（）AA primary key must exist for creation of a clustered indexBA clustered index allows fulltext searching within InnoDBCThe first unique index is always used as a clustered index and not a primary keyDA clustered index provides direct access to a page containing row dataEIf no indexes exist, a hidden clustered index is generated based on row IDsFA primary key is used as a clustered indexGA clustered index is a grouping of indexes from different tables into a global index for faster searching
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.
单选题View the Exhibit and examine the structure of the EMP table. You executed the following command to add a primary key to the EMP table： ALTER TABLE emp ADD CONSTRAINT emp_id_pk PRIMARY KEY （emp_id） USING INDEX emp_id_idx； Which statement is true regarding the effect of the command？（）A The PRIMARY KEY is created along with a new index.B The PRIMARY KEY is created and it would use an existing unique index.C The PRIMARY KEY would be created in a disabled state because it is using an existing index.D The statement produces an error because the USING clause is permitted only in the CREATE TABLE command.
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 are true about the primary key constraint in a table？ （）AIt is not possible to disable the primary key constraint.BIt is possible to have more than one primary key constraint in a single table.CThe primary key constraint can be referred by only one foreign key constraint.DThe primary key constraint can be imposed by combining more than one column.EThe non-deferrable primary key constraint creates an unique index on the primary key column if it is not already indexed.
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