PostgreSQL pgces-02 online test

PostgreSQL CE 8 Silver Exam

What students need to know about the pgces-02 exam

Total None Questions & Answers

Question 1

Select two suitable statements regarding the following SQL statement:
CREATE TRIGGER trigger_1 AFTER UPDATE ON sales FOR EACH ROW EXECUTE PROCEDURE
write_log();

A. It is defining a trigger "trigger_1".
B. Every time 'UPDATE' is executed on the "sales" table, the "write_log" function is called once.
C. The "write_log" function is called before 'UPDATE' takes place.
D. 'UPDATE' is not executed if "write_log" returns NULL.
E. 'DROP TRIGGER trigger_1 ON sales;' deletes the defined trigger.

Answer:

A, E

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Question 2

Select two transaction isolation levels supported in PostgreSQL.

A. DIRTY READ
B. READ COMMITTED
C. REPEATABLE READ
D. PHANTOM READ
E. SERIALIZABLE

Answer:

B, E

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Question 3

PostgreSQL can use an index to access a table. Select two incorrect statements about indexes.

A. An index is created by 'CREATE INDEX', and deleted by 'DROP INDEX'.
B. By using an index effectively, searching and sorting performs faster.
C. There are B-tree, Hash, R-tree and GiST index types.
D. By creating an index, performance always improves.
E. Creating an unused index does not affect the performance of a database at all.

Answer:

D, E

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Question 4

Select two incorrect statements regarding 'DOMAIN'.

A. When defining a domain, you can add a default value and constraints to the original data.
B. Domain is a namespace existing between databases and objects such as tables.
C. A domain is created by 'CREATE DOMAIN'.
D. A domain can be used as a column type when defining a table.
E. To define a domain, both input and output functions are required.

Answer:

B, E

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Question 5

Select two suitable statements regarding the data types of PostgreSQL.

A. One field can handle up to 1GB of data.
B. 'n' in CHARACTER(n) represents the number of bytes.
C. Only the INTEGER type can be declared as an array.
D. There is a non-standard PostgreSQL data type, called Geometric data type, which handles 2dimensional data.
E. A large object data type can be used to store data of unlimited size.

Answer:

A, D

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Question 6

The table "score" is defined as follows:
gid | score
-----+-------
1 | 70 1 |
60 2 | 100
3 | 80 3 |
50
The following query was executed. Select the number of rows in the result.
SELECT gid, max(score) FROM score GROUP BY gid HAVING max(score) > 60;

A. 1 row
B. 2 rows
C. 3 rows
D. 4 rows
E. 5 rows

Answer:

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Question 7

Table "t1" is defined as follows: CREATE TABLE t1 (value VARCHAR(5)); A set of SQL statements were
executed in the following order. Select the number of rows that table "t1" has after execution. BEGIN;
INSERT INTO t1 VALUES ('AA'); SAVEPOINT point1; INSERT INTO t1 VALUES ('BB'); SAVEPOINT point2;
INSERT INTO t1 VALUES ('CC'); ROLLBACK TO point1; INSERT INTO t1 VALUES ('DD'); END;

A. 1 row
B. 2 rows
C. 3 rows
D. 4 rows
E. 0 rows

Answer:

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Question 8

Select two suitable statements about sequences.

A. A sequence always returns a 4-byte INTEGER type value, so the maximum value is 2147483647.
B. A sequence is defined by 'CREATE SEQUENCE', and deleted by 'DROP SEQUENCE'.
C. Although the "nextval" function is called during a transaction, it will have no effect if that transaction is rolled back.
D. A sequence always generates 0 or consecutive positive numbers.
E. A sequence number can be set by calling the "setval" function.

Answer:

B, E

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Question 9

The "sample" table consists of the following data: How many rows are returned by executing the
following SQL statement? SELECT DISTINCT ON (data) * FROM sample;

A. 2 rows
B. 3 rows
C. 4 rows D. 5 rows
E. 6 rows

Answer:

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Question 10

The following SQL statements were executed using psql.
Select the appropriate statement about the result.
LISTEN sign_v; BEGIN; NOTIFY sign_v; COMMIT;
LISTEN sign_v;

A. At the point that 'NOTIFY sign_v' is executed, a message that starts with "Asynchronous notification 'sign_v' received" is output.
B. At the point that 'COMMIT' is executed, a message that starts with "Asynchronous notification 'sign_v' received" is output.
C. At the point that 'SELECT * FROM pg_user;" is executed, a message that starts with "Asynchronous notification 'sign_v' received" is output.
D. When 'LISTEN sign_v' is executed for the second time, a message that starts with "Asynchronous notification 'sign_v' received" is output.
E. The message "Asynchronous notification 'sign_v' received" is not received while in this connection.

Answer:

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