单项选择题
In which scenario would index be most useful? （）
A. The indexed column is declared as NOT NULL.
B. The indexed columns are used in the FROM clause.
C. The indexed columns are part of an expression.
D. The indexed column contains a wide range of values.
相关考题
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多项选择题
Which two are attributes of /SQL*Plus? （）
A. /SQL*Plus commands cannot be abbreviated.
B. /SQL*Plus commands are accesses from a browser.
C. /SQL*Plus commands are used to manipulate data in tables.
D. /SQL*Plus commands manipulate table definitions in the database.
E. /SQL*Plus is the Oracle proprietary interface for executing SQL statements. -
单项选择题
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE You issue these statements: CREATE table new_emp ( employe_id NUMBER, name VARCGAR2(30)); INSERT INTO new_emp SELECT employee_id, last_name from employees; Savepoint s1; UPDATE new_emp set name = UPPER(name); Savepoint s2; Delete from new_emp; Rollback to s2; Delete from new_emp where employee_id=180; UPDATE new_emp set name = James; Rollback to s2; UPDATE new_emp sey name = James Where employee_id=180; Rollback; At the end of this transaction, what is true? （）
A. You have no rows in the table.
B. You have an employee with the name of James.
C. You cannot roll back to the same savepoint more than once.
D. Your last update fails to update any rows because employee ID 180 was already deleted. -
单项选择题
Mary has a view called EMP_DEPT_LOC_VU that was created based on the EMPLOYEES,DEPARTMENTS, and LOCATIONS tables. She granted SELECT privilege to Scott on this view. Which option enables Scott to eliminate the need to qualify the view with the name MARY .EMP_DEP_LOC_VU each time the view is referenced? （）
A. Scott can create a synonym for the EMP_DEPT_LOC_VU bus using the command: CREATE PRIVATE SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonymn.
B. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command: CREATE SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonym.
C. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command: CREATE LOCAL SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonym.
D. Scott cannot create a synonym because synonyms can be created only for tables.
E. Scott cannot create any synonym for Mary's view. Mary should create a private synonym for the view and grant SELECT privilege on that synonym to Scott.
