CHAPTER 2Implementing a Database

Introduction to Creating Databases• After you’ve installed the Oracle software, the next logical

step is to create a database.• DBAs must know how to configure required operating

system variables, directories, and the initialization file before creating the database.

• As part of creating the database the data dictionary must be instantiated.

• After the database is created it needs to be made available for remote Oracle Net connections by configuring and starting a listener.

Creating a Database• Database Configuration Assistant utility• CREATE DATABASE statement

Operating System Variables• Manually setting• Using Oracle provide scripts• DBA home grown script

Creating a Database

1. Set the operating system variables

2. Configure the initialization file

3. Create required directories

4. Create the database

5. Create the data dictionary

6. Run pupbld.sql as SYSTEM

OS Variables that Oracle Uses• ORACLE_HOME• PATH• ORACLE_SID• LD_LIBRARY_PATH

Initialization File versus Spfile• Spfile is required by some Oracle products• Spfile is modifiable via ALTER SYSTEM• Spfile on server will be used by remote clients for

operations such as starting up the database

• Initialization text file can be edited directly with an OS editor (like vi)

• Comments can be placed in a text file

Configure Initialization File

ORACLE_HOME/dbs/init<SID>.ora

db_name

db_block_size

memory_target

control_files

undo_management

undo_tablespace

Security Related Initialization Parameters

sql92_security=TRUE

os_authent_prefix='‘

global_names=TRUE

audit_sys_operations=TRUE

audit_trail='DB'

Create Required Directories• Follow standards (OFA or standards for your environment)• Directories to contain: datafiles, control files, online redo

log files• 10g and lower requires creation of directories that

background processes can write to

Crafting a CREATE DATABASE statementCREATE DATABASE O11R2

maxlogfiles 16

maxlogmembers 4

maxdatafiles 1024

maxinstances 1

maxloghistory 680

character set "UTF8"

DATAFILE '/ora01/dbfile/O11R2/system01.dbf'

SIZE 500m

EXTENT MANAGEMENT LOCAL

UNDO TABLESPACE undotbs1 DATAFILE '/ora02/dbfile/O11R2/undotbs01.dbf'

SIZE 800m

SYSAUX DATAFILE '/ora03/dbfile/O11R2/sysaux01.dbf'

SIZE 200m

DEFAULT TEMPORARY TABLESPACE temp TEMPFILE '/ora03/dbfile/O11R2/temp01.dbf'

SIZE 800m

DEFAULT TABLESPACE users DATAFILE '/ora02/dbfile/O11R2/users01.dbf'

SIZE 20m

LOGFILE GROUP 1

('/ora02/oraredo/O11R2/redo01a.rdo',

'/ora03/oraredo/O11R2/redo01b.rdo') SIZE 100m,

GROUP 2

('/ora02/oraredo/O11R2/redo02a.rdo',

'/ora03/oraredo/O11R2/redo02b.rdo' ) SIZE 100m,

GROUP 3

('/ora02/oraredo/O11R2/redo03a.rdo',

'/ora03/oraredo/O11R2/redo03b.rdo' ) SIZE 100m

USER sys IDENTIFIED BY secretfoo

USER system IDENTIFIED BY secretfoobar;

Tablespaces Initially Created• SYSTEM• SYSAUX• UNDO• TEMP• USERS

SYS versus SYSTEM• SYS is like superuser• SYS owns all data dictionary objects• SYS has all privileges (start/stop database)

• SYSTEM is a database account that has the DBA role granted to it

• Some shops lock the SYSTEM account and don’t use it (because it’s usually the first account a hacker will try to access)

Create the Database

1. Create CREATE DATABASE statement

2. Connect as SYS and startup nomount

3. Run CREATE DATABASE statement

4. Create the data dictionary (must be done as SYS)

5. Run the pupbld.sql script as SYSTEM

Creating the Data Dictionary

SQL> connect / as sysdba

SQL> @?/rdbms/admin/catalog.sql

SQL> @?/rdbms/admin/catproc.sql

• What does the “?” translate to in the prior statements?• What do these scripts actually create?• Why do you need to be connected as SYS when creating

the data dictionary

Creating a Listener• Listener required for connections from remote clients• ORACLE_HOME/network/admin default location for

Oracle Net files• Consider setting a variable like TNS_ADMIN that points to

default location for Oracle Net files• lnsrctl utility

Listener Security ConsiderationsPASSWORDS_INVPRD=f00bar

#

ADMIN_RESTRICTIONS_INVPRD=ON

#

LOG_FILE_INVPRD=invlistener.log

LOG_DIRECTORY_INVPRD=/orahome/app/oracle/product/11.2.0.2/db_1/network/log

#

TRACE_FILE_INVPRD=invlistener.trc

TRACE_DIRECTORY_INVPRD=/orahome/app/oracle/product/11.2.0.2/db_1/network/trace

#

LOG_STATUS=ON

#

INBOUND_CONNECT_TIMEOUT_INVPRD2=60

Named ListenerINVPRD =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = 131.147.127.152)(PORT = 1528))))

SID_LIST_INVPRD =

(SID_LIST =

(SID_DESC =

(GLOBAL_DBNAME = INVPRD)

(ORACLE_HOME = /orahome/app/oracle/product/11.2.0.2/db_1)

(SID_NAME = INVPRD)))

Creating a Password File• Optional• Allows remote connections to the database as SYS• orapw utility

Operating System Authentication• OS group of dba and oper assigned when installing the

Oracle software• Any OS user belonging to dba group can connect to the

database without a password

$ sqlplus / as sysdba

SQL> show user;

USER is “SYS”

SYSDBA vs. SYSOPER• SYSDBA contains all privileges• SYSOPER can start/stop, alter, toggle archivelog mode

and recover the database

Starting a Database• Nomount: background processes and memory allocated,

only file accessed at this point is the initialization file• Mount: Control files opened. Datafiles and online redo

logs not opened.• Open: Datafiles and online redo logs opened

sqlplus / as sysdba

SQL> startup;

Stopping a Database

sqlplus / as sysdba

SQL> shutdown immediate;

• NORMAL• TRANSACTIONAL• TRANSACTIONAL LOCAL• IMMEDIATE• ABORT

Database vs. Instance• Database consists of datafiles, controlfiles, and online

redo log files• Instance consists of background processes and memory

structures.

Using Database Configuration Assistant

• Good way to consistently create databases (when used with a response file)

• dbca utility

Dropping a Database• Be very careful• Permanently drops datafiles, control files and online redo

logs• You are not prompted• There is no undrop database command

How many Oracle Homes on one Database Server• One set of Oracle binaries for each database?• One set of Oracle binaries for all databases?• Different versions of Oracle binaries• Security considerations?• Hardware resource considerations?

One Database or Many Databases on One Server• One database per each application• Shared database with different users and tablespaces for

each application• Security considerations?• Hardware resource considerations?

Summary• Creating a database is a critical DBA task.• The database should be created in a consistent, secure,

and maintainable manner.• As part of creating a database, a listener must be

configured to allow for remote connections to the database via Oracle Net.