ch01.htm

来自「Teach yourself Oracle8 in 21 day」· HTM 代码 · 共 550 行 · 第 1/3 页

<P>Let's look at these roles and responsibilities and determine what skills are necessary
to fulfill these duties. Here the roles and responsibilities are divided into two
categories: basic duties and additional duties. The dividing line between these is
not clear; there is significant overlap.
<H3><FONT COLOR="#000077"><B>Basic Duties of the DBA</B></FONT></H3>
<P>Here are some of the basic roles of the Oracle DBA. This is not an all-inclusive
list. Depending on your installation and staff, your duties might not include all
of these, or might include many more items. This section is simply intended as a
general guide.

<UL>
	<LI>Installation of new software--It is primarily the job of the DBA to install new
	versions of Oracle software, application software, and other software related to
	DBMS administration. It is important that the DBA or other IS staff members test
	this new software before it is moved into a production environment.
	<P>
	<LI>Configuration of hardware and software with the system administrator-- In many
	cases the system software can only be accessed by the system administrator. In this
	case, the DBA must work closely with the system administrator to perform software
	installations, and to configure hardware and software so that it functions optimally
	with the DBMS.
	<P>
	<LI>Security administration--One of the main duties of the DBA is to monitor and
	administer DBMS security. This involves adding and removing users, administering
	quotas, auditing, and checking for security problems.
	<P>
	<LI>Performance tuning and monitoring--The DBA must continually monitor system performance
	and be prepared to retune the system as necessary. Even a well-tuned system must
	be constantly monitored and adjusted. Sometimes this involves changing tuning parameters,
	other times this involves rebuilding an index or restructuring a table.
	<P>
	<LI>Backup and recovery--Perhaps the most important responsibility of the DBA is
	protecting the data in the system. To effectively do this, you must develop an effective
	backup and recovery strategy and make sure it is carried out. A DBA's chief responsibility
	is to maintain the integrity of the database. It is important that the backup and
	recovery process be periodically tested.
	<P>
	<LI>Routine scheduled maintenance--It is the job of the DBA to schedule routine DBMS
	maintenance and carry out this maintenance. This maintenance is regularly carried
	out in the early hours of the morning or on weekends when this maintenance causes
	the least inconvenience to the user community.
	<P>
	<LI><FONT COLOR="#000000">Troubleshooting:</FONT>--In the event of a system or DBMS
	failure, it is the job of the DBA to troubleshoot or assist in the<FONT COLOR="#000000">
	Troubleshooting: </FONT>of the problem. The DBA might also participate in or lead
	the effort to find and eliminate problems or potential problems.
	<P>
	<LI>Failure recovery--Because a system failure can mean that the users do not have
	access to their data, it can be the job of the DBA to lead efforts to recover from
	system failures. The well-prepared DBA has contingency plans for system outages and
	can soon have the DBMS running again.
</UL>

<H3><FONT COLOR="#000077"><B>Additional Duties of the DBA</B></FONT></H3>
<P>Some of the more advanced duties of the Oracle DBA might include the following:

<UL>
	<LI>Data analysis--The DBA will frequently be called on to analyze the data stored
	in the database and to make recommendations relating to performance and efficiency
	of that data storage. This might relate to the more effective use of indexes or the
	use of some feature such as the Parallel Query option.
	<P>
	<LI>Database design (preliminary)--The DBA is often involved at the preliminary database-design
	stages. Through the involvement of the DBA, many problems that might occur can be
	eliminated. The DBA knows the DBMS and system, can point out potential problems,
	and can help the development team with special performance considerations.
	<P>
	<LI>Data modeling and optimization--By modeling the data, it is possible to optimize
	the system layout to take the most advantage of your I/O subsystem.
	<P>
	<LI>Assisting developers with SQL and stored procedure development--The DBA should
	be prepared to be a resource for developers and users. The DBA is often called on
	to help with SQL problems as well as to design and write stored procedures.
	<P>
	<LI>Enterprise standards and naming conventions--Because many different groups might
	perform different roles in developing and deploying applications, it is often the
	DBA who is called on to help define enterprise standards and naming conventions as
	well as to ensure that new applications are conforming to these standards.
	<P>
	<LI>Development of production migration procedures--Because the DBA is responsible
	for the availability and reliability of the DBMS and applications using that DBMS,
	it is up to the DBA to develop and maintain procedures for rolling out new applications
	and DBMS software. This involves evaluating new software or patches as well as testing
	them. It is up to the DBA to guarantee the stability and robustness of the system.
	<P>
	<LI>Environmental documentation--The DBA should document every aspect of the DBMS
	environment, including hardware configuration and maintenance records, software updates,
	changes to the applications and DBMS, and all other items related to changes made
	to the system. The DBA should be able to access these records and fully reproduce
	the current system as necessary.
	<P>
	<LI>Consult with development team and end users--The DBA is often called on to act
	as a consultant to the development team as well as to the user community. This might
	involve personally assisting a single user or developing training courses for the
	user community as a whole.
	<P>
	<LI>Evaluation of new software--The DBA might be called on to evaluate new software
	and make recommendations based on that evaluation. This might be related to a software
	purchase or a scheduled rollout of a new version of software. This evaluation must
	be done in the context of the stability of the system. It is your responsibility
	to maintain system stability and reliability.
	<P>
	<LI>Evaluation of new hardware and software purchases--There is much consideration
	involved in purchasing new hardware and software. Much of this consideration involves
	the functionality and compatibility of the software or hardware as well as the cost
	of these components. Although the cost of the item is not usually a concern of the
	DBA, the functionality and compatibility is. The DBA might be asked to make recommendations
	based on whether these purchases make sense.
	<P>
	<LI>Capacity planning and sizing--Determining whether it is necessary to purchase
	new hardware or software to meet increased loads is often a job for the DBA. Capacity
	planning and sizing is important to provide the level of service your users require.
	By anticipating the future needs of your users, you can provide an excellent level
	of service with no interruptions.
</UL>

<H2><FONT COLOR="#000077"><B>Summary</B></FONT></H2>
<P>This lesson introduces some of the topics you will see in the rest of the book.
First you saw a brief history of how Oracle got where it is today. Then you examined
number of terms that you will see throughout the book. These terms are important;
you will use them every day in your job as a DBA. Finally, you were presented with
some of your tasks and responsibilities as a DBA.
<H2><FONT COLOR="#000077"><B>What's Next?</B></FONT></H2>
<P>Tomorrow's lesson examines the structure and operation of Oracle. By having an
understanding of how Oracle works, you can better understand how to administer it.
You will look at some of the new features in Oracle8, as well as receive an overview
of Oracle performance.
<H2><FONT COLOR="#000077"><B>Q&amp;A</B></FONT></H2>

<DL>
	<DD><FONT COLOR="#000000"><B>Q What units of measurement are typically used in databases?</B></FONT>
	<P><FONT COLOR="#000000"><B>A</B></FONT> With Oracle systems you usually discuss
	size in terms of megabytes and gigabytes, but some systems are growing into the terabyte
	range.</P>
	<P><FONT COLOR="#000000"><B>Q Are the duties of the DBA the same for all companies?</B></FONT></P>
	<P><FONT COLOR="#000000"><B>A</B></FONT> No, far from it. No two sites are the same.
	Although the basic duties and responsibilities might be similar, the extended duties
	are always different.</P>
	<P><FONT COLOR="#000000"><B>Q Why is it important to document?</B></FONT></P>
	<P><FONT COLOR="#000000"><B>A</B></FONT> If you document the system configuration
	and logging changes, you will have a much easier time reproducing the system in the
	event of a failure. By having configuration information in a log book you can save
	numerous hours of trial and error in reconfiguring the system.
</DL>

<H2><FONT COLOR="#000077"><B>Workshop</B></FONT></H2>
<P>The workshop provides quiz questions to help you solidify your understanding of
the material covered. For answers to quiz questions, see Appendix A, &quot;Answers.&quot;
<H3><FONT COLOR="#000077"><B>Quiz</B></FONT></H3>

<DL>
	<DD><B>1. </B>How is a DBMS different from a database?
	<P><B>2.</B> What is a DDL statement?</P>
	<P><B>3. </B>What is a DML statement?</P>
	<P><B>4.</B> What are some of the characteristics of an OLTP system?</P>
	<P><B>5. </B>What are some of the characteristics of a DSS system?</P>
	<P><B>6. </B>State five duties of an Oracle DBA.</P>
	<P><B>7. </B>What is the most important duty of an Oracle DBA?
</DL>

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