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多选题You create a table with the PERIOD FOR clause to enable the use of the Temporal Validity feature of Oracle Database 12c. Examine the table definition: Which three statements are true concerning the use of the Valid Time Temporal feature for the EMPLOYE
题目
The valid time columns employee_time_start and employee_time_end are automatically created.
The same statement may filter on both transaction time and valid temporal time by using the AS OF TIMESTAMP and PERIOD FOR clauses.
The valid time columns are not populated by the Oracle Server automatically.
The valid time columns are visible by default when the table is described.
Setting the session valid time using DBMS_FLASHBACK_ARCHIVE.ENABLE_AT_VALID_TIME sets the visibility for data manipulatio
相似问题和答案
第1题：
You are the administrator of a SQL Server 2000 computer in your company's personnel department. Employee data is stored in a SQL Server 2000 database. A portion of the database schema is shown in the exhibit.
You want to create a text file that lists these data columns in the following format title, FirstName, LastName, WorkPhone, PositionName, DepartmentName.
You want to create the text file as quickly as possible. You do not expect to re-create this file, and you want to avoid creating new database objects if possible.
What should you do?
A．Use the bcp utility to export data from each table to a separate text file. Use format files to select the appropriate columns. Merge the data from each text file into a single text file.
B．Create a view that joins data from all three tables include only the columns you want to appear in the text file. Use the bcp utility to export data from the view.
C．Create a SELECT query that joins the data from the appropriate columns in the three tables. Add an INTO clause to the query to create a local temporary table. Use the bcp utility to export data from the local temporary table to a text file.
D．Create a SELECT query that joins the data from the appropriate columns in the three tables. Add an INTO clause to the query to create a global temporary table. Use the bcp utility to export data from the global temporary table to a text file.
解析：Explanation:Asthecolumnsthatwewantinthetextfileareondifferenttablesinthedatabase,wewouldhavetocombinethecolumnintoatableorview.Becausewewillnotneedtoreproducethefile,wecanwecancombinethecolumnfromthevarioustablesintoaglobaltemporarytablebyusingtheSELECTINTOstatement.Thenweusethebcputilitytoexportthedatafromtheglobaltemporaryfiletoatextfile.Note:Temporarytablesarenotstoredinthecurrentdatabase;theyarestoredinthetempdbsystem.Therearetwotypesoftemporarytables:localtemporarytables,whicharevisibleonlytotheconnectionthatcreatedthem,andglobaltemporarytables,thatarevisibletoallconnections.Ifglobaltemporarytablesarenotdroppedexplicitlybeforetheconnectionthatcreatedthemdisconnects,theyaredroppedassoonasallothertasksstopreferencingthem.Nonewtaskscanreferenceaglobaltemporarytableaftertheconnectionthatcreateditdisconnects.ThebcputilitycopiesdatabetweenaninstanceofSQLServer2000andadatafileinauser-specifiedformat.ItcanbeusedtotransferdatafromaSQLServertabletoadatafileforuseinotherprograms.Furthermore,datacanalsobetransferredoutbyspecifyingaSELECTstatement.Thebcputilitycanuseglobaltemporarytables,butnotlocaltemporarytables.IncorrectAnswers:A:CreatingaglobaltemporarytablebyusingtheSELECTstatementandusingthebcputilitytoexportdatafromthattablewouldrequirelessadministrativeeffortthanusingbcptoexporttherequiredcolumnsfromeachtableintoaseparatetextfileandthenmergingthosetextfilesintoasingletextfile.B:Becausewewouldnotneedtore-createthedatafileagain,itwouldbeeasiertousetheSELECTstatementtocreateaglobaltemporarytableasthesetablesaredroppedautomaticallywhennothingreferencethem.C:Thebcputilitycannotuselocaltemporarytables.Note:Temporarytablesarenotstoredinthecurrentdatabase;theyarestoredinthetempdbsystem.Therearetwotypesoftemporarytables:localtemporarytables,whicharevisibleonlytotheconnectionthatcreatedthem,andglobaltemporarytables,thatarevisibletoallconnections.
第2题：
Which two are true about aggregate functions?（）
- A、You can use aggregate functions in any clause of a SELECT statement.
- B、You can use aggregate functions only in the column list of the select clause and in the WHERE clause of a SELECT statement.
- C、You can mix single row columns with aggregate functions in the column list of a SELECT statement by grouping on the single row columns.
- D、You can pass column names, expressions, constants, or functions as parameter to an aggregate function.
- E、You can use aggregate functions on a table, only by grouping the whole table as one single group.
- F、You cannot group the rows of a table by more than one column while using aggregate functions.
正确答案:A,E
第3题：
A. An error is generated.
B. You will have two identical tables in the HR schema with different names.
C. You create a table called employees in the HR schema based on you EMP table.
D. You create an alternative name for the employees table in the HR schema in your own schema.
第4题：
The accounting manager wants you to create a form that when queried will display a calculated total of year-to-date actual expenditures for the found code entered. The values needed to generate this summary data are stored in multiple tables. Which data source type can you assign to the data block for this form without having the DBA create a database object?（）
- A、database table
- B、transactional trigger
- C、stored procedure
- D、FROM clause query
- E、client-side procedure
正确答案:D
第5题：
You want the size of the tablespace to increase when it is full. Which option would you use？（）
- A、use automatic extent allocation
- B、disable threshold for the tablespace
- C、use freelists to manage the free space
- D、use automatic segment space management
- E、create the tablespace as a bigfile tablespace
- F、use the RESIZE clause while creating the tablespace
- G、enable AUTOEXTEND for at least one of the data files in the tablespace
正确答案:G
第6题：
Exhibit:
UPDATE EzonexamConsolidated
SET District = ‘Mexico’
WHERE RtvID = 45
You work as database administrator at Ezonexam.com. You handle one SQL Server 2000 computer and one database.
When users run the query in the exhibit above the receive the following error message:
Server: Mrh3612, Level 16, Stats 1, Line 1
View or function ‘EzonexamConsolidated’ is not updateable because it
contains aggregates:
How should you enable the query to run?
A．Create a non-normalized EzonexamConsolidated table and populate the table with data from the base tables.
B．The appropriate users should be granted UPDATE permissions on each base table.
C．To enable updates on the composite tables create an INSTEAD OF trigger on the view.
D．On each base table add a cascading update trigger.
解析：Explanation:SQLServer2000usesINSTEADOFtriggersandpartitionedviewstoenhancetheclassofupdateableviews.INSTEADOFtriggerscanbecreatedonaviewinordertomakeaviewupdateable.TheINSTEADOFtriggerisexecutedinsteadofthedatamodificationstatementonwhichthetriggerisdefined.Thistriggerallowstheusertospecifythesetofactionsthatneedtotakeplaceinordertoprocessthedatamodificationstatement.Thus,ifanINSTEADOFtriggerexistsforaviewonagivendatamodificationstatement,thecorrespondingviewisupdateablethroughthatstatement.Iftheviewisapartitionedview,theviewisupdateable,subjecttocertainrestrictions.IncorrectAnswers:A:Creatingatablethatcombinesthecompositetablesthattheviewisbasedonwoulddenyustheabilitytousetheviewtoreturnaggregatedcolumnvalues.B:Theerrormessageisnotrelatedtopermissionsbuttotheupdateableofthetable.D:CascadingreferentialintegrityconstraintsmakesitpossibletodefinetheactionsSQLServer2000takeswhenauserattemptstodeleteorupdateakeytowhichexistingforeignkeyspoint.CascadingreferentialintegrityconstraintsfireAFTERtriggersafterallofthecascadingreferentialactionsdirectlycausedbytheoriginalDELETEorUPDATEareperformed.
第7题：
You are designing an application for a telecom company and you have been asked to design a database table to facilitate monthly bill generation. The bill would include details of customer calls， listed in chronological order. Which method would you follow to achieve this objective without increasing the overhead of sorting the rows？（）
- A、create a hash cluster to store the data
- B、create an index cluster to store the data
- C、create a partitioned table to store the data
- D、create a sorted hash cluster to store the data
- E、create a heap table with rowid to store the data
正确答案:D
第8题：
In your multitenant container database (CDB) containing pluggable database (PDBs), you granted theCREATE TABLE privilege to the common user C A_ADMIN in root and all PDBs. You execute thefollowing command from the root container:SQL >REVOKE create table FROM C A_ADMIN;What is the result?（）
A. It executes successfully and the CREATE TABLE privilege is revoked from C # # A_ADMIN in root only.
B. It fails and reports an error because the CONTAINER=ALL clause is not used.
C. It excludes successfully and the CREATE TABLE privilege is revoked from C # # A_ADMIN in root and all PDBs.
D. It fails and reports an error because the CONTAINER=CURRENT clause is not used.
E.It executes successfully and the CREATE TABLE privilege is revoked from C # # A_ADMIN in all PDBs.
第9题：
A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLEcommand with the ENABLE VALIDATE option to enable the constraint that was disabled. What are the twoeffects of this command（）
- A、It fails if any existing row violates the constraint.
- B、It does not validate the existing data in the table.
- C、It enables the constraint to be enforced at the end of each transaction.
- D、It prevents insert， update， and delete operations on the table while the constraint is in the process of beingenabled
正确答案:A,D
第10题：
You are shrinking the SCOTT.EMP table by executing the ALTER TABLE SCOTT.EMP SHRINK SPACE CASCADE statement. What is a prerequisite for shrinking the SCOTT.EMP table？（）
- A、 You must enable the block change tracking feature.
- B、 You must have enable the flashback feature.
- C、 You must use the OMF in your database.
- D、 You must define the tablespace of the SCOTT.EMP table for automatic segment space management.
正确答案:D