PostgreSQL PGCES-02 Quiz 1 Topic 3 Questions 1-5

Question: 1

Select three SQL statements which return NULL.

ASELECT 0 = NULL;

BSELECT NULL != NULL;

CSELECT NULL IS NULL;

DSELECT NULL;

ESELECT 'null'::TEXT;

Show Answer

Question: 2

The table "t1" is defined below. The column "id"

for table "t1" is of INTEGER type.

id | name ----

+-----------1 |

mammoth 2 |

tortoise 3 |

coelacanth

The following SQL statements were executed. Select the correct statement about the execution result. BEGIN; DECLARE c SCROLL CURSOR FOR SELECT name FROM t1 ORDER BY id;

MOVE FORWARD 2 FROM c; FETCH FORWARD ALL FROM c; COMMIT;

AThe number of rows returned by the FETCH statement is 0.

BThe number of rows returned by the FETCH statement is 1.

CThe number of rows returned by the FETCH statement is 2.

DThe number of rows returned by the FETCH statement is 3.

EAn error occurs part way through.

Show Answer

Question: 3

Select two incorrect descriptions regarding the following SQL statements.

CREATE TABLE cities ( name text,

population float ); CREATE

TABLE capitals ( state

char(2) ) INHERITS

(cities);

ADefines the tables called 'cities' and 'capitals'.

B'capitals' inherits 'cities'.

CSearching 'capitals' also searches rows in 'cities'.

DThe columns 'name' and 'population' are also defined in 'capitals'.

EThe second SQL statement results in an error, since the 'INHERITS' keyword is no longer available.

Show Answer

Question: 4

There is a table "tb1" that has a column "c1" defined as type TEXT. The following SQL is executed while client "A" is connected. BEGIN; LOCK TABLE tb1 IN ACCESS EXCLUSIVE MODE; SELECT * FROM tb1; While the above 'SELECT' statement is being executed, client "B" connects to the same database and executes the following SQL. Select two correct statements describing the behavior of PostgreSQL. INSERT INTO tb1 (c1) VALUES ('new line'); Note: the default transaction isolation level is set to "read committed".

AThe process for client 'B' is blocked until the current connection for client 'A' is finished.

BThe process for client 'B' is blocked until the current transaction for client 'A' is finished.

CThe process for client 'B' will be deleted regardless of the condition of client 'A'.

DThe process of client 'B' will affect the SELECT result of client 'A'.

EThe process of client 'B' will not affect the SELECT result of client 'A'.

Show Answer

Question: 5

Select one incorrect statement about the command shown below.

Note: $ is the command prompt. $ dropuser -U admin foo

AIf there is a database owned by foo, an error will occur.

BIf admin is not the owner of foo, an error will occur.

CIf admin doesn't have the superuser privilege, an error will occur.

DThe user admin is removing the user foo.

EThe same process can be performed using the SQL command 'DROP USER'.

Show Answer

PostgreSQL PGCES-02 Quiz:1 Topic:3 Questions:1-5