PostgreSQL-CE PGCES-02 問題集

質問 1：
Select two suitable statements regarding a postmaster process.
A. A postmaster process receives and processes database queries.
B. A postmaster process collects statistical information.
C. A postmaster process is created for each client connection.
D. A postmaster process waits for client connection requests.
E. A postmaster process creates a child process which processes the given queries.
正解：D,E

質問 2：
Select one incorrect statement about schemas.
A. One user cannot own multiple schemas.
B. 'DROP SCHEMA' deletes a schema.
C. A new schema is created by 'CREATE SCHEMA'.
D. 'SELECTcurrent_schema();' returns the current schema.
E. A schema is the name space for a database object.
正解：A

質問 3：
I would like to insert the contents of the text file users.dat into the table t1 using psql. Contents of
text file users.dat:
Definition of table t1:
CREATE TABLE t1 (uname TEXT, pass TEXT, id INTEGER); Select the most appropriate input
from those below.
A. \insert t1 FROM users.dat WITH DELIMITER ':';
B. INSERT INTO t1 FROM file('users.dat');
C. INSERT INTO t1SELECT uname, pass, id FROM file('users.dat');
D. \copy t1 FROM users.dat WITH DELIMITER ':'
E. \copy t1 TO users.dat WITH DELIMITER ':'
正解：D

質問 4：
Select two commands below from which privileges cannot be changed by the GRANT and
REVOKE statements.
A. DROP
B. TRIGGER
C. DELETE
D. VACUUM
E. SELECT
正解：A,D

質問 5：
A table is defined as follows:
CREATE TABLE t (id INT, val TEXT);
Select two correct statements from below about the function "get_head" defined below. CREATE
FUNCTION get_head(BOOLEAN)
RETURNS TEXT LANGUAGE sql CALLED ON NULL INPUT
AS 'SELECT val FROM t WHERE $1 OR id > 0 ORDER BY id LIMIT 1;';
A. There are cases where this function returns multiple lines.
B. When NULL is passed for the argument and the function is executed, NULL is returned.
C. If a function with the same name and with type BOOLEAN as the parameter is already defined, an error occurs.
D. This function is defined using PL/pgSQL.
E. Even if this function is passed the same parameter value and executed multiple times, the returned values will not necessarily also be the same value.
正解：C,E

質問 6：
Select the most suitable statement about the creation of a new database.
A. You can set the character encoding when creating a new database.
B. The target directory is specified by the environment variable PGDATA or the -D parameter when creating a database.
C. Only one database can be used at the same time even if two or more databases are created.
D. Only a PostgreSQL superuser is authorized to create a new database.
E. Only the OS superuser (root) can create databases.
正解：A