What is true about updates through a v...

单项选择题What is true about updates through a view?（）

A.You cannot update a view with group functions.
B.When you update a view group functions are automatically computed.
C.When you update a view only the constraints on the underlying table will be in effect.
D.When you update a view the constraints on the views always override the constraints on the underlying tables.

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1.单项选择题 Click the Exhibit button and examine the data from the ORDERS and CUSTOMERS tables.
Evaluate the SQL statement:
SELECT *
FROM orders
WHERE cust_id = (SELECT cust_id
FROM customers
WHERE cust_name = 'Smith');
What is the result when the query is executed?（）

A.A
B.B
C.C
D.D
E.E

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2.单项选择题 The EMP table contains these columns:
EMPLOYEE_ID NUMBER(4)
EMPNAME VARCHAR2 (25)
SALARY NUMBER(9,2)
HIRE_DATE DATE
You query the database with this SQL statement:
SELECT empname,hire_date HIREDATE, salary
FROM EMP
ORDER BY hire_date;
How will the results be sorted?（）

A.randomly
B.ascending by date
C.descending by date
D.ascending alphabetically
E.descending alphabetically

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3.单项选择题Which is an iSQL*Plus command?（）

A.INSERT
B.UPDATE
C.SELECT
D.DESCRIBE
E.DELETE
F.RENAME

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4.单项选择题Which iSQL*Plus feature can be used to replace values in the WHERE clause?（）

A.substitution variables
B.replacement variables
C.prompt variables
D.instead-of variables
E.This feature cannot be implemented through iSQL*Plus.

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5.多项选择题Which four statements correctly describe functions that are available in SQL? （）

A.INSTR returns the numeric position of a named character.
B.NVL2 returns the first non-null expression in the expression list.
C.TRUNCATE rounds the column, expression, or value to n decimal places.
D.DECODE translates an expression after comparing it to each search value.
E.TRIM trims the heading or trailing characters (or both) from a character string.
F.NVL compares two expressions and returns null if they are equal, or the first expression if they are not equal.
G.NULLIF compares two expressions and returns null if they are equal, or the first expression if they are not equal.

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6.单项选择题 Examine the description of the EMPLOYEES table:
EMP_ID NUMBER(4) NOT NULL LAST_
NAME VARCHAR2(30) NOT NULL
FIRST_NAME VARCHAR2(30)
DEPT_ID NUMBER(2)
JOB_CAT VARCHAR2(30)
SALARY NUMBER(8,2)
Which statement shows the department ID, minimum salary, and maximum salary paid in that department, only if the minimum salary is less than 5000 and maximum salary is more than 15000?（）

A.SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) < 5000 AND MAX(salary) > 15000;
B.SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) < 5000 AND MAX(salary) > 15000 GROUP BY dept_id;
C.SELECT dept_id, MIN(salary), MAX(salary) FROM employees HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;
D.SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;
E.SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id, salary HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;

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7.多项选择题Which are DML statements? （）

A.COMMIT
B.MERGE
C.UPDATE
D.DELETE
E.CREATE
F.DROP...

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8.单项选择题In which case would you use a FULL OUTER JOIN?（）

A.Both tables have NULL values.
B.You want all unmatched data from one table.
C.You want all matched data from both tables.
D.You want all unmatched data from both tables.
E.One of the tables has more data than the other.
F.You want all matched and unmatched data from only one table.

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9.单项选择题You need to change the definition of an existing table. The COMMERCIALS table needs its DESCRIPTION column changed to hold varying length characters up to 1000 bytes. The column can currently hold 500 bytes per value. The table contains 20000 rows. Which statement is valid?（）

A.ALTER TABLE commercials MODIFY (description CHAR2(1000));
B.ALTER TABLE commercials CHANGE (description CHAR2(1000));
C.ALTER TABLE commercials CHANGE (description VARCHAR2(1000));
D.ALTER TABLE commercials MODIFY (description VARCHAR2(1000));
E.You cannot increase the size of a column if the table has rows.

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10.单项选择题You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty. Which statement accomplishes this task?（）

A.ALTER TABLE students ADD PRIMARY KEY student_id;
B.ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);
C.ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;
D.ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
E.ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);

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