DAT 380 Wk 4 – Practice: Knowledge Check

The special operator used to check whether a subquery returns any rows is _____.

EXISTS

BETWEEN

ANSI-standard SQL allows the use of special operators in conjunction with the WHERE clause.

True

False

You can select partial table contents by naming the desired fields and by placing restrictions on the rows to be included in the output.

True

False

A database language enables the user to perform complex queries designed to transform the raw data into useful information.

True

False

Which query is used to list a unique value for V_CODE, where the list will produce only a list of those values that are different from one another?

SELECT UNIQUE V_CODE

FROM PRODUCT;

SELECT DISTINCT V_CODE

FROM PRODUCT;

SELECT DIFFERENT V_CODE

FROM PRODUCT;

SELECT ONLY V_CODE

FROM PRODUCT;

In Oracle, _____ make(s) it possible to merge SQL and traditional programming constructs, such as variables, conditional processing (IF-THEN-ELSE), basic loops (FOR and WHILE loops,) and error trapping.

Procedural Language SQL

embedded SQL

dynamic SQL

stored procedures

All changes in a table structure are made using the _____ TABLE command, followed by a keyword that produces the specific changes a user wants to make.

ALTER

UPDATE

ROLLBACK

COMMIT

The _____ constraint is used to validate data when an attribute value is entered.

UNIQUE

CASCADE

SET NULL

CHECK

_____ is a relational set operator.

EXISTS

PLUS

EXCEPT

The SQL data manipulation command HAVING:

restricts the selection of grouped rows based on a condition.

modifies an attribute’s values in one or more table’s rows.

groups the selected rows based on one or more attributes.

restricts the selection of rows based on a conditional expression.