PostgreSQL-CE PGCES-02 問題集

質問 1：
Select the SQL command that must be executed prior to executing the EXECUTE command.
A. LOAD
B. PREPARE
C. ALLOCATE
D. CREATE FUNCTION
E. DECLARE
正解：B

質問 2：
Select two incorrect statements concerning the system catalog.
A. It stores the object definition information for tables and columns.
B. It is defined based on the standard SQL specification.
C. There may be changes to specification by major version upgrades.
D. It stores the internal information of the database management system.
E. It is accessible as a table; however, it is output in binary format so it can not be read as is.
正解：B,E

質問 3：
The table "t1" is defined by the following SQL statement: CREATE TABLE t1 (id integer, name
varchar(20));
You want to increase the execution speed of the SQL statement below:
SELECT id, name FROM t1 WHERE id < 123 AND upper(name) = 'MAMMOTH'; Select the most
suitable SQL statement to create an index.
A. CREATE INDEX t1_idx ON t1 USING HASH (id);
B. ALTER TABLE ADD INDEX ON t1 (id,upper(name));
C. ALTER TABLE ADD INDEX ON t1 (id, name);
D. CREATE INDEX t1_idx ON t1 (id,upper(name));
E. CREATE INDEX t1_idx ON t1 (name);
正解：D

質問 4：
Select the correct result generated by execution of the following SQL statements: CREATE
TABLE log (id int, message TEXT, logtime TIMESTAMP);
CREATE TABLE log_01 () INHERITS (log);
INSERT INTO log_01 VALUES (1, 'error', CURRENT_TIMESTAMP); SELECT * FROM log;
A. First 'CREATE TABLE' generates a syntax error.
B. Second 'CREATE TABLE' generates a syntax error.
C. 'SELECT' statement returns 1 row, and exits successfully.
D. 'INSERT' statement generates an error stating that the number of columns and values do not match".
E. 'SELECT' statement returns 0 rows, and exits successfully.
正解：C

質問 5：
The table "custom" is defined below.
The "id" column and "introducer" column are of INTEGER type, and the "email" column is of
TEXT type.
id | email | introducer
----+-----------------+------------
2 | [email protected] | 1
3 | [email protected] | 2
4 | [email protected] | 2
Three SQL statements were executed in the following order: UPDATE custom SET email = ''
FROM custom c
WHERE custom.introducer = c.id;
UPDATE custom SET introducer = NULL
WHERE introducer NOT IN (SELECT id FROM custom);
DELETE FROM custom WHERE id = 2 OR introducer = 2;
Select the number of rows in the "custom" table after the execution.
A. 4 rows
B. 0 rows
C. 2 rows
D. 3 rows
E. 1 row
正解：B

質問 6：
Select the most appropriate statement about the initdb command.
A. It can only be executed by the user who installed PostgreSQL.
B. The directory designated by the environment variable PGDATA must exist.
C. It can not be executed by an OS administrator-level user (root user).
D. Unless the environment variable PGDATA is set, it can not be executed.
E. When "auto" is designated as the value for the environment variable PGDATA, a directory is automatically set up.
正解：C