DBA Fundamentals I 1-42
Practice 1: Solutions
1 Which one of the following statements is true?
a An Oracle server is a collection of data consisting of three file types.
b A user establishes a connection with the database by starting an Oracle instance.
c A connection is a communication pathway between the Oracle Server and the
Oracle Instance.
d A session starts when a user is validated by the Oracle server.
2 Which one of the following memory areas is not part of the SGA?
a Database buffer cache
b PGA
c Redo log buffer cache
d Shared Pool
3 Which two of the following statements are true about the Shared Pool?
a The shared Pool consists of the Library Cache, Data Dictionary Cache, Shared SQL
area, Java Pool, and Large Pool.
b The Shared Pool is used to store the most recently executed SQL statements and the
most recently used data.
c The Shared Pool is used for object that can be shared globally.
d The Library Cache consist of the Shared SQL and Shared PL/SQL areas.
4 Which one of the following memory areas is used to cache the data dictionary
information?
a Database Buffer Cache
b PGA
c Redo log buffer cache
d Shared Pool
5 The primary purpose of the Redo Log Buffer Cache is to record all changes to the
database data blocks.
a True
b False
Answer: True
6 The PGA is a memory region that contains data and control information for multiple
server processes or multiple background processes.
a True
b False
7 Which one of the following processes is available when an Oracle instance is started.
a User process
b Background process
c Server process
d System process
8 Identify the six mandatory background processes.
________________________________________
________________________________________
________________________________________
________________________________________
________________________________________
________________________________________
9 Which one of the following memory areas is used to cache the data dictionary
information?
a Database Buffer Cache
b PGA
c Redo log buffer cache
d Shared Pool
10 Match the process with its task.
a Database Writer ___ Assists with writing to the data file headers
b Log Writer ___ Responsible for instance recovery
c System Monitor ___ Cleans up after failed processes
d Process Monitor ___ Records database changes for recovery purposes
e Checkpoint ___ Writes dirty buffers to the data files
11 The physical structure of an Oracle database consists of control files, data files, and
redo log files.
a True
b False
12 Place the following structures in order of hierarchy beginning with database.
a Tablespaces
b Extent
c Segment
d database
e block
Saturday, September 29, 2007
Thursday, September 27, 2007
UNIX FAQS
5. How do you change File Access Permissions?
Every file has following attributes:
> owner's user ID ( 16 bit integer )
> owner's group ID ( 16 bit integer )
> File access mode word
'r w x -r w x- r w x'
(user permission-group permission-others permission)
r-read, w-write, x-execute
To change the access mode, we use chmod(filename,mode).
Example 1:
To change mode of myfile to 'rw-rw-r--' (ie. read, write permission for user - read,write permission for group - only read permission for others) we give the args as:
chmod(myfile,0664) .
Each operation is represented by discrete values
'r' is 4
'w' is 2
'x' is 1
Therefore, for 'rw' the value is 6(4+2).
Example 2:
To change mode of myfile to 'rwxr--r--' we give the args as:
chmod(myfile,0744).
6. What are links and symbolic links in UNIX file system?
A link is a second name (not a file) for a file. Links can be used to assign more than one name to a file, but cannot be used to assign a directory more than one name or link filenames on different computers.
Symbolic link 'is' a file that only contains the name of another file.Operation on the symbolic link is directed to the file pointed by the it.Both the limitations of links are eliminated in symbolic links.
Commands for linking files are:
Link ln filename1 filename2
Symbolic link ln -s filename1 filename2
7. What is a FIFO?
FIFO are otherwise called as 'named pipes'. FIFO (first-in-first-out) is a special file which is said to be data transient. Once data is read from named pipe, it cannot be read again. Also, data can be read only in the order written. It is used in interprocess communication where a process writes to one end of the pipe (producer) and the other reads from the other end (consumer).
8. How do you create special files like named pipes and device files?
The system call mknod creates special files in the following sequence.
1. kernel assigns new inode,
2. sets the file type to indicate that the file is a pipe, directory or special file,
3. If it is a device file, it makes the other entries like major, minor device numbers.
For example:
If the device is a disk, major device number refers to the disk controller and minor device number is the disk.
Every file has following attributes:
> owner's user ID ( 16 bit integer )
> owner's group ID ( 16 bit integer )
> File access mode word
'r w x -r w x- r w x'
(user permission-group permission-others permission)
r-read, w-write, x-execute
To change the access mode, we use chmod(filename,mode).
Example 1:
To change mode of myfile to 'rw-rw-r--' (ie. read, write permission for user - read,write permission for group - only read permission for others) we give the args as:
chmod(myfile,0664) .
Each operation is represented by discrete values
'r' is 4
'w' is 2
'x' is 1
Therefore, for 'rw' the value is 6(4+2).
Example 2:
To change mode of myfile to 'rwxr--r--' we give the args as:
chmod(myfile,0744).
6. What are links and symbolic links in UNIX file system?
A link is a second name (not a file) for a file. Links can be used to assign more than one name to a file, but cannot be used to assign a directory more than one name or link filenames on different computers.
Symbolic link 'is' a file that only contains the name of another file.Operation on the symbolic link is directed to the file pointed by the it.Both the limitations of links are eliminated in symbolic links.
Commands for linking files are:
Link ln filename1 filename2
Symbolic link ln -s filename1 filename2
7. What is a FIFO?
FIFO are otherwise called as 'named pipes'. FIFO (first-in-first-out) is a special file which is said to be data transient. Once data is read from named pipe, it cannot be read again. Also, data can be read only in the order written. It is used in interprocess communication where a process writes to one end of the pipe (producer) and the other reads from the other end (consumer).
8. How do you create special files like named pipes and device files?
The system call mknod creates special files in the following sequence.
1. kernel assigns new inode,
2. sets the file type to indicate that the file is a pipe, directory or special file,
3. If it is a device file, it makes the other entries like major, minor device numbers.
For example:
If the device is a disk, major device number refers to the disk controller and minor device number is the disk.
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