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访问hbase？table中的行，以下可操作的是（）
- A、全表扫描
- B、通过单个row？key访问
- C、通过row？key的range
- D、通过列族来访问
参考答案
更多 “访问hbase？table中的行，以下可操作的是（）A、全表扫描B、通过单个row？key访问C、通过row？key的rangeD、通过列族来访问” 相关考题
考题
Examine the data in the EMPLOYEES and DEPARTMENTS tables:Also examine the SQL statements that create the EMPLOYEES and DEPARTMENTS tables:On the EMPLOYEES table, EMPLOYEE_ID is the primary key.MGR_ID is the ID of managers and refers to the EMPLOYEE_ID.DEPT_ID is foreign key to DEPARTMENT_ID column of the DEPARTMENTS table.On the DEPARTMENTS table, DEPARTMENT_ID is the primary key.Examine this DELETE statement:What happens when you execute the DELETE statement?（）A. Only the row with department ID 40 is deleted in the DEPARTMENTS table.B. The statement fails because there are child records in the EMPLOYEES table with department ID 40.C. The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 110 and 106 are deleted from the EMPLOYEES table.D. The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 106 and 110 and the employees working under employee 110 are deleted from the EMPLOYEES table.E. The row with department ID 40 is deleted in the DEPARTMENTS table. Also all the rows in the EMPLOYEES table are deleted.F. The statement fails because there are no columns specifies in the DELETE clause of the DELETE statement.
考题
What type of constraint is used to ensure that each row inserted into the EMPLOYEE table with a value in the WORKDEPT column has a row with a corresponding value in the DEPTNO column of the DEPARTMENT table?（）A.A check constraint on the EMPLOYEE tableB.A unique constraint on the EMPLOYEE table WORKDEPT columnC.A foreign key reference from the DEPARTMENT tables DEPTNO column to the WORKDEPT column of the EMPLOYEE tableD.A foreign key reference from the EMPLOYEE tables WORKDEPT column to the DEPTNO column of the DEPARTMENT table
考题
Which of the following scenarios will ensure that the value of the NEXT_STEPNO column in a given row of table TABLEX exists as a value of column STEPNO (usually in another row) in the same table?()
A.Define a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.B.Define a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).C.Define column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.D.Define column NEXT_STEPNO as the primary key of TABLEX and column STEPNO as a foreign key referencing column NEXT_STEPNO in the same table.
考题
以下关于COW和ROW快照的说法正确的是？（）A、COW共有3次数据访问和1次元数据更新B、COW共有1次数据访问和1次元数据更新C、ROW共有3次数据访问和1次元数据更新D、ROW共有1次数据访问和1次元数据更新
考题
为表TEST中ID列添加主键约束的语法是（）A、ALTER TABLE TEST CHANGE（ ID INT PRIMARY KEY）B、ALTER TABLE TEST ADD（ ID INT PRIMARY KEY）C、ALTER TABLE TEST MODIFY（ ID INT PRIMARY KEY）D、ALTER TABLE TEST ADD CONSTRAINT PK PRIMARY KEY （ID）
考题
您在公司的数据库中成功创建了名为SALARY的表。您现在要通过向引用EMPLOYEES表的匹配列的SALARY表添加FOREIGNKEY约束条件来建立EMPLOYEES表与SALARY表之间的父/子关系。尚未向SALARY表添加任何数据。应执行以下哪条语句（）A、ALTER TABLE salary ADD CONSTRAINT fk_employee_id_01 FOREIGN KEY（employee_id）REFERENCES employees（employee_id）B、ALTER TABLE salary ADD CONSTRAINT fk_employee_id_ FOREIGN KEY BETWEEN salary（employee_id）AND employees（employee_id）C、ALTER TABLE salary FOREIGN KEY CONSTRAINT fk_employee_id_REFERENCES employees（employee_id）D、ALTER TABLE salary ADD CONSTRAINT fk_employee_id_FOREIGN KEY salary（employee_id）=employees（employee_id）
考题
Which of the following scenarios will ensure that the value of the NEXT_STEPNO column in a given row of table TABLEX exists as a value of column STEPNO (usually in another row) in the same table?（）A、Define a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.B、Define a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).C、Define column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.D、Define column NEXT_STEPNO as the primary key of TABLEX and column STEPNO as a foreign key referencing column NEXT_STEPNO in the same table.
考题
You work in a company which uses SQL Server 2008. You are the administrator of the company database. Now you are in charge of a SQL Server 2008 instance. There is a database named named Dworks in the instance. The Dworks table has a table named BillDetails which has a clustered primary key named BillId on the BillId column. The BillDetails table has a single XML column named GoodsDetails. The XML column has an XML index and XML data are stored in this XML column. A new column named GoodsID is added to the BillDetails table. GoodsID must be included in the primary key. So what action should you perform to achieve this goal？（） A、You should drop the XML index on the table. Modify the primary key. Recreate the XML index B、You should alter the XML index and set the ALLOW_ROW_LOCKS = OFF option. Alter the primary key and set the ALLOW_ROW_LOCKS = ON option. C、You should move the XML data to a temporary table. Clear the XML data from the original table by setting the GoodsDetails column to NULL. Modify the primary key. Repopulate the ProductSpecs column. D、You should disable the XML index on the GoodsDetails column. Modify the primary key.Enable the XML index on the ProductSpecs column.
考题
What type of constraint is used to ensure that each row inserted into the EMPLOYEE table with a value in the WORKDEPT column has a row with a corresponding value in the DEPTNO column of the DEPARTMENT table?（）A、A check constraint on the EMPLOYEE tableB、A unique constraint on the EMPLOYEE table WORKDEPT columnC、A foreign key reference from the DEPARTMENT tables DEPTNO column to the WORKDEPT column of the EMPLOYEE tableD、A foreign key reference from the EMPLOYEE tables WORKDEPT column to the DEPTNO column of the DEPARTMENT table
考题
Which of the following will be a consequence of defining the column IDCOL2 in TABLE2 as a foreign key referencing the primary key (IDCOL1) of TABLE1?（）A、DB2 will no longer allow updating the value of IDCOL1 in TABLE1.B、When inserting a row in TABLE2, the only values that DB2 will allow for IDCOL2 are the existing values of IDCOL1.C、When inserting a row in TABLE2, DB2 will only allow foreign values for IDCOL2, that is values which do not exist in IDCOL1.D、When a SELECT statement joins TABLE1 with TABLE2, DB2 will automatically add the condition TABLE1.IDCOL1=TABLE2.IDCOL2 if not specified in the statement.
考题
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
考题
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？（）A、null lock on the row being updatedB、null lock on the table containing the rowC、ROW SHARE lock for the row being updatedD、ROW EXCLUSIVE lock for the row being updatedE、shared row-exclusive lock for the row being updatedF、a shareable table lock for the table containing the rowG、exclusive table-level lock for the table containing the row
考题
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.
考题
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？（）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.
考题
单选题Which of the following scenarios will ensure that the value of the NEXT_STEPNO column in a given row of table TABLEX exists as a value of column STEPNO (usually in another row) in the same table?（）A
Define a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.B
Define a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).C
Define column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.D
Define column NEXT_STEPNO as the primary key of TABLEX and column STEPNO as a foreign key referencing column NEXT_STEPNO in the same table.
考题
单选题Which of the following will be a consequence of defining the column IDCOL2 in TABLE2 as a foreign key referencing the primary key (IDCOL1) of TABLE1?（）A
DB2 will no longer allow updating the value of IDCOL1 in TABLE1.B
When inserting a row in TABLE2, the only values that DB2 will allow for IDCOL2 are the existing values of IDCOL1.C
When inserting a row in TABLE2, DB2 will only allow foreign values for IDCOL2, that is values which do not exist in IDCOL1.D
When a SELECT statement joins TABLE1 with TABLE2, DB2 will automatically add the condition TABLE1.IDCOL1=TABLE2.IDCOL2 if not specified in the statement.
考题
单选题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.
考题
单选题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
考题
单选题您在公司的数据库中成功创建了名为SALARY的表。您现在要通过向引用EMPLOYEES表的匹配列的SALARY表添加FOREIGNKEY约束条件来建立EMPLOYEES表与SALARY表之间的父/子关系。尚未向SALARY表添加任何数据。应执行以下哪条语句（）A
ALTER TABLE salary ADD CONSTRAINT fk_employee_id_01 FOREIGN KEY（employee_id）REFERENCES employees（employee_id）B
ALTER TABLE salary ADD CONSTRAINT fk_employee_id_ FOREIGN KEY BETWEEN salary（employee_id）AND employees（employee_id）C
ALTER TABLE salary FOREIGN KEY CONSTRAINT fk_employee_id_REFERENCES employees（employee_id）D
ALTER TABLE salary ADD CONSTRAINT fk_employee_id_FOREIGN KEY salary（employee_id）=employees（employee_id）
考题
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？（）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.
考题
单选题Oracle数据库中，通过（）访问能够以最快的方式访问表中的一行（）。A
主键B
RowidC
唯一索引D
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