单选题You want to capture column group usage and gather extended statistics for better cardinality estimates for the CUSTOMERS table in the SH schema. Examine the following steps: 1. Issue the SELECT DBMS_STATS.CREATE_EXTENDED_STATS (‘SH’, ‘CUSTOMERS’) FROM

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单选题

You want to capture column group usage and gather extended statistics for better cardinality estimates for the CUSTOMERS table in the SH schema. Examine the following steps: 1. Issue the SELECT DBMS_STATS.CREATE_EXTENDED_STATS (‘SH’, ‘CUSTOMERS’) FROM dual statement. 2. Execute the DBMS_STATS.SEED_COL_USAGE (null, ‘SH’, 500) procedure. 3. Execute the required queries on the CUSTOMERS table. 4. Issue the SELECT DBMS_STATS.REPORT_COL_USAGE (‘SH’, ‘CUSTOMERS’) FROM dual statement. Identify the correct sequence of steps.（）

3，2，1，4

2，3，4，1

4，1，3，2

3，2，4，1

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第1题

You executed the following commands:Which statement is correct regarding the above statistics collection on the SH.CUSTOMERS table in the above session?()A. The statistics are stored in the pending statistics table in the data dictionary.B. The statistics are treated as the current statistics by the optimizer for all sessions.C. The statistics are treated as the current statistics by the optimizer for the current sessions only.D. The statistics are temporary and used by the optimizer for all sessions until this session terminates.

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第2题

You need to produce a report for mailing labels for all customers. The mailing label must have only the customer name and address. The CUSTOMERS table has these columns:CUST_ID NUMBER(4) NOT NULLCUST_NAME VARCHAR2(100) NOT NULLCUST_ADDRESS VARCHAR2(150)CUST_PHONE VARCHAR2(20)Which SELECT statement accomplishes this task?（）A. SELECT* FROM customers;B. SELECT name, address FROM customers;C. SELECT id, name, address, phone FROM customers;D. SELECT cust_name, cust_address FROM customers;E. SELECT cust_id, cust_name, cust_address, cust_phone FROM customers;

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第3题

Examine the following command that is executed for the TRANSPORT table in the SH schema:Which statement describes the significance of this command?()A. It collects statistics into the pending area in the data dictionaryB. It creates a virtual hidden column in the CUSTOMERS_OBE tableC. It collects statistics with AUTO_SAMPLE_SIZE for ESTIMATE_PERCENTD. It creates a histogram to hold skewed information about the data in the columns

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第4题

Youexecutedthefollowingcommands：SQL>ALTERSESSIONSETOPTIMIZER_USE_PENDING_STATISTICS=false；SQL>EXECUTEDBMS_STATS.SET_TABLE_PREFS（’SH’，’CUSTOMERS’，’PUBLISH’，’false’）；SQL>EXECUTEDBMS_STATS.GATHER_TABLE_STATS（’SH’，’CUSTOMERS’）；WhichstatementiscorrectregardingtheabovestatisticscollectionontheSH.CUSTOMERStableintheabovesession？（）A.Thestatisticsarestoredinthependingstatisticstableinthedatadictionary.B.Thestatisticsaretreatedasthecurrentstatisticsbytheoptimizerforallsessions.C.Thestatisticsaretreatedasthecurrentstatisticsbytheoptimizerforthecurrentsessionsonly.D.Thestatisticsaretemporaryandusedbytheoptimizerforallsessionsuntilthissessionterminates.

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第5题

Which three statements are true about SQL plan directives?()A. They are tied to a specific statement or SQL id.B. They instruct the maintenance job to collect missing statistics or perform dynamic sampling to generate a more optimal plan.C. They are used to gather only missing statistics.D. They are created for a query expression where statistics are missing or the cardinality estimates by the optimizer are incorrect.E. They instruct the optimizer to create only column group statistics.F. Improve plan accuracy by persisting both compilation and execution statistics in the SYSAUX tablespace.

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第6题

You need to generate a list of all customer last names with their credit limits from the CUSTOMERS table. Those customers who do not have a credit limit should appear last in the list. Which two queries would achieve the required result?（）A、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit DESCB、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limitC、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit NULLS LASTD、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_last_name, cust_credit_limit NULLSLAST

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第7题

The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER(4) NOT NULL CUSTOMER_NAME VARCHAR2(100) NOT NULL STREET_ADDRESS VARCHAR2(150) CITY_ADDRESS VARCHAR2(50) STATE_ADDRESS VARCHAR2(50) PROVINCE_ADDRESS VARCHAR2(50) COUNTRY_ADDRESS VARCHAR2(50) POSTAL_CODE VARCHAR2(12) CUSTOMER_PHONE VARCHAR2(20) The CUSTOMER_ID column is the primary key for the table. Which two statements find the number of customers? （） A、SELECT TOTAL(*) FROM customer;B、SELECT COUNT(*) FROM customer;C、SELECT TOTAL(customer_id) FROM customer;D、SELECT COUNT(customer_id) FROM customer;E、SELECT COUNT(customers) FROM customer;F、SELECT TOTAL(customer_name) FROM customer;

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单选题You want to capture column group usage and gather extended statistics for better cardinality estimates for the CUSTOMERS table in the SH schema. Examine the following steps: 1. Issue the SELECT DBMS_STATS.CREATE_EXTENDED_STATS (‘SH’, ‘CUSTOMERS’) FROM

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