多项选择题
Which four are correct guidelines for naming database tables? （）
A. Must begin with either a number or a letter.
B. Must be 1-30 characters long.
C. Should not be an Oracle Server reserved word.
D. Must contain only A-Z, a-z, 0-+, _, *, and #.
E. Must contain only A-Z, a-z, 0-9, _, $, and #.
F. Must begin with a letter.
相关考题
-
多项选择题
Which two statements about sequences are true? （）
A. You use a NEXTVAL pseudo column to look at the next possible value that would be generated from a sequence, without actually retrieving the value.
B. You use a CURRVAL pseudo column to look at the current value just generated from a sequence, without affecting the further values to be generated from the sequence.
C. You use a NEXTVAL pseudo column to obtain the next possible value from a sequence by actually retrieving the value from the sequence.
D. You use a CURRVAL pseudo column to generate a value from a sequence that would be used for a specified database column.
E. If a sequence starting from a value 100 and incremented by 1 is used by more then one application, then all of these applications could have a value of 105 assigned to their column whose value is being generated by the sequence.
F. You use REUSE clause when creating a sequence to restart the sequence once it generates the maximum value defined for the sequence. -
单项选择题
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) DEFAULT SA_REP SAL NUMBER COMM_PCT NUMBER MGR_ID NUMBER DEPARTMENT_ID NUMBER You need to update the records of employees 103 and 115. The UPDATE statement you specify should update the rows with the values specified below: JOB_ID: Default value specified for this column definition. SAL: Maximum salary earned for the job ID SA_REP. COMM_PCT: Default value specified for this commission percentage column, if any. If no default value is specified for the column, the value should be NULL. DEPARTMENT_ID: Supplied by the user during run time through substitution variable. Which UPDATE statement meets the requirements?（）
A. UPDATE employees SET job_id = DEFAULT AND Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP') AND comm_pct = DEFAULT AND department_id = &did WHERE employee _id IN (103,115);
B. UPDATE employees SET job_id = DEFAULT AND Sal = MAX(sal) AND comm_pct = DEFAULT OR NULL AND department_id = &did WHERE employee_id IN (103,115) AND job _ id = 'SA_ REP';
C. UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP'), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115);
D. UPDATE employees SET job_id = DEFAULT, Sal = MAX(sal), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115) AND job _ id = 'SA_ REP';
E. UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP') comm_pct = DEFAULT OR NULL, department_id = &did WHERE employee_id IN (103,115); -
多项选择题
Which three statements about subqueries are true?（）
A. A single row subquery can retrieve only one column and one row.
B. A single row subquery can retrieve only one row but many columns.
C. A multiple row subquery can retrieve multiple rows and multiple columns.
D. A multiple row subquery can be compared by using the ">" operator.
E. A single row subquery can use the IN operator.
F. A multiple row subquery can use the "=" operator.
