An update in a leaf row takes place.
The index becomes invalid after the update.
The leaf block containing the row to be updated is marked as invalid.
A row in the leaf block of the index for the key value is logically deleted and a new leaf row is inserted
第1题：
A.Define the column MAINID as NOT UPDATABLE
B.Define the column MAINID as a PRIMARY KEY
C.Define the column MAINID as a FOREIGN KEY
D.Define an UPDATE trigger on table TABLEX
第2题：
A warehouse fact table in your Oracle 12c Database is range-partitioned by month and accessed frequently with queries that span multiple partitions The table has a local prefixed, range partitioned index. Some of these queries access very few rows in some partitions and all the rows in other partitions, but these queries still perform a full scan for all accessed partitions. This commonly occurs when the range of dates begins at the end of a month or ends close to the start of a month. You want an execution plan to be generated that uses indexed access when only a few rows are accessed from a segment, while still allowing full scans for segments where many rows are returned. Which three methods could transparently help to achieve this result?（）
第3题：
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
第4题：
Which statement describes the effect on an index， when the indexed column for the rows is updatedin the base table（）
第5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？（）
第6题：
Which of the following can be used to ensure that once a row has been inserted in table TABLEX, the column MAINID in that row cannot be updated?（）
第7题：
Which two statements are true regarding B-tree indexs（）
第8题：
You have altered a non-unique index to be invisible to determine if queries execute within an acceptable response time without using this index.Which two are possible if table updates are performed which affect the invisible index columns?（）
A. The index remains invisible.
B. The index is not updated by the DML statements on the indexed table.
C. The index automatically becomes visible in order to have it updated by DML on the table.
D. The index becomes unusable but the table is updated by the DML.
E. The index is updated by the DML on the table.
第9题：
Which two operations can be performed on an external table（）
第10题：
User Scott has updated the salary of one of the employees in the EMPLOYEES table and has not committed the transaction. What are the two types of locks that this scenario would lead to？（）