Oracle Database Administration for Microsoft SQL Server DBAs part 3 potx

D
atabase administrators (DBAs) have significant responsibilities.
They must not only provide reliable access to company data,
but also protect that data, monitor the database environment,
troubleshoot problems, and more. If the lives of DBAs were
simple, what fun would that be? That is probably why
I enjoy the job so much—because of the different opportunities and challenges
that I get to face day to day.
To provide a stable and highly available database environment, along
with planning backups and performing recoveries and all the other
maintenance tasks, DBAs are usually exploring how to use new features,
and even learning multiple database platforms. Yes, I said it: as a DBA, you
probably need to know more than one database platform. The days of being
just an Oracle or SQL Server DBA are probably gone. Companies are
adopting more than one database platform, and applications may import or
export data from one database system to another. But why am I telling you
this? You have already decided to add Oracle to your arsenal. The big
question is, How hard will this be?
If you are a SQL Server DBA, you don’t need to start back at square one
to support Oracle databases. Certainly, there are differences between the
platforms, but many of the DBA tasks are basically the same. You can apply
the skills you already have to learning Oracle, using this book as your
guide. This book will even translate terms from SQL Server to Oracle,
because sometimes being able to speak the language is half of the battle.
Before we look into the specifics of Oracle, in this chapter, we will
review the role of the DBA, so you can see how to leverage the skills you
already have as you learn the new database platform. We will also look
briefly at the migration process.
General DBA Skills
The role of the DBA is more than just backing up the database and making
sure the database is available. There are several hats that are worn by a

DBA—from tuning queries to server configuration, as well as making sure
the database is secure.
Here are some of the tasks a DBA performs:
■
Installing databases
■
Backing up and restoring databases
2
Oracle Database Administration for Microsoft SQL Server DBAs
■
Troubleshooting problems and errors
■
Coding and tuning SQL statements
■
Monitoring space and growth
■
Establishing best practices
■
Configuring highly available environments
■
Developing security strategies
■
Performing maintenance tasks
On a given day, a DBA may need to validate backups, handle some
support issues, add users, and possibly roll out some new code to the
production database. Some days may be spent just troubleshooting
performance, tuning code, or working on the database model. Even if the
production database might not need to be restored on a regular basis (a very
good thing!), a test environment may need to be refreshed frequently. Being
able to resolve an issue as quickly as possible is important, which may

require research and drilling through database logs and trace files.
Other general skills for a DBA might include managing projects and
creating and following processes. DBAs are not working in an environment
where only one person is accessing the database system. The database is
normally supporting enterprise-level applications with many users and
various workloads.
Software vendors have stated that installing databases and monitoring
them are simple tasks, but somehow there seems to be more moving parts
these days. Also, new areas, such as compliance and business intelligence,
provide different challenges for DBAs.
The DBA may have the responsibility to back up databases and restore
and copy them into another environment. The DBA may be required to
design the database model and coding procedures. A DBA may even be
more of an enterprise architect, who knows how to use data at an enterprise
level to support the business and add value through business intelligence
solutions. This type of role would also involve assessing if the right tool is
being used, understanding the differences in platforms, and managing these
to help make better design decisions.
Chapter 1: The Database Administrator
3
Where Do DBAs Belong
in an Organization?
Are DBAs in production support, the architecture team, the engineering
team, or the development team? Actually, they could probably be a part of
all these teams or in a separate group altogether. But in any case, they still
need to work with all the teams.
DBAs work with system administrators for configuring operating systems
and providing input to hardware decisions for the environment. DBAs work
with developers to design systems and provide coding standards and best
practices for developing applications that use databases. DBAs work with

networking and interface teams for connections and hooks into the
database. DBAs work with users, operations, and anyone else who needs
access to the database. DBAs are considered to be experts in the area of
databases, and they are expected to know enough information in other
areas to be able to support and communicate needs for the database
environment. Some DBAs may even be considered engineers instead of
administrators, which implies more of a design and architecture type of role
than production support.
Depending on the size of the company and number of databases, there
might be one DBA who does it all, or separate DBAs, such as a system DBA,
an application DBA, a development DBA, and an architecture DBA. In
following compliance regulations, the separation of these roles for the DBAs
is becoming more important.
Just as application developers shouldn’t have access to the production
system, the development DBA may just be working in the development
space, and passing scripts to production support DBAs for execution. The
development DBA could be working with the developers on the design of
the database application, developing the data model and data flows. The
role might involve looking at performance and coding SQL, as well as
seeing how best to implement new features.
The system DBA will concentrate on backups, space monitoring, and
maintenance jobs like reviewing statistics and rebuilding indexes. This DBA
would probably be the one who provides production support and runs
prepared scripts for changing objects or implementing upgrades.
The roles for DBAs also depend on whether applications are developed
in-house or third-party applications are running in the environment.
4
Oracle Database Administration for Microsoft SQL Server DBAs
Database Installation Planning
Several pieces need to be coordinated and communicated to install and

upgrade databases. Basic installations wouldn’t need much planning if we
were just installing software on a desktop somewhere and the application
was used by just one person. Also, an organization will probably need more
than just one database, so a repeatable process would be useful.
DBAs need to manage installations to be able to communicate needs to
other teams for hardware and operating system configurations. They must
get details about the application to make sure that the database has the
features needed. Properly managing database installations is important for
planning upgrades and implementing enterprise monitoring systems. On a
smaller scale, this planning is useful for patching, making changes to
security configurations, and rolling out auditing tools. Developing standards
and building a process will create a more consistent and stable database
environment.
When installing SQL Server, you can choose where to put data files and
log files, if the instance is the default unnamed or named instance, which
patch set is to be applied, if Reporting Services and Analysis Services are to
be installed, and so on. You probably have a checklist so that a standard
installation can be repeated on multiple databases. Creating a checklist or
standard installation document is just as important for Oracle databases.
Instance names, parameters that should be set, components that should be
installed, Oracle home directories, directories for data files and log files, as
well as recovery areas, should all be included. Table 1-1 shows high-level
checklists for preparing to install SQL Server and Oracle databases. Notice
that many of the same tasks are listed for both platforms. (Chapter 3 covers
Oracle installation in detail.)
Leveraging Skills
We’ve reviewed some general DBA skills and practices, which you are
probably currently applying to support the SQL Server system you are
managing. Now let’s look at how these skills provide a starting point for
learning Oracle.

Chapter 1: The Database Administrator
5
Table 1-2 compares the skills needed for managing SQL Server databases
with those required for managing Oracle databases.
You probably expected that these tasks and skills are needed no matter
which database platform is being supported and managed. The trick is
discovering the differences, such as new best practices, variations in
features, and differences in syntax for these tasks in Oracle. This way, you
can distinguish what you already know from what you need to learn.
For example, whether the database is Oracle or SQL Server, part of the
DBA’s job is to make sure things are backed up properly, including having a
strategy for the types of backups required. Recovery and restore procedures
are also part of this strategy. You already understand general backup
concepts. You know that you want transaction log backups and to be able
to recover up to a point in time, as you’ve set up in SQL Server. Now you
need to know the details of backup and restore options in Oracle. For
example, to create a backup in SQL Server, you execute a backup database
command; in Oracle, using the RMAN utility, you execute a backup
database command—that’s simple enough, right?
6
Oracle Database Administration for Microsoft SQL Server DBAs
SQL Server Oracle
Obtain software and release notes Obtain software and release notes
Configure Windows, memory, etc. Validate operating system
configuration
Set up domain account and
privileges
Create user for installing Oracle and
processes (other users might be
needed for other components)

Allocate storage Allocate storage
Configure network Configure network
Install software Install software
Validate install Validate install
Back up system, excluding .mdf
and .ldf files
Back up system, excluding data files
TABLE 1-1.
SQL Server and Oracle Installation Checklists
System monitoring is another example. Understanding why certain areas
need to be monitored for better-running databases is half of the battle. If you
know the information you want to monitor, then you just need to find out
how to do it in Oracle. Knowing which areas to check comes from the
experience of dealing with databases and troubleshooting issues in the past.
Performing health checks against the database and reviewing database logs
are good first steps.
Health checks are not just looking into current issues, but also monitoring
several areas and verifying that databases are running well. Health checks in
SQL Server could be verifying if jobs are running properly, checking disk
space, reviewing last-analyzed-for statistics, making sure old backups have
been purged, and running other monitoring scripts. Oracle’s high-level list of
health checks include validating backups, checking available space in
tablespaces and file systems, making sure statistics are up to date, and
verifying that other scripts are running and completing as expected.
Chapter 1: The Database Administrator
7
Task/Skill SQL Server Oracle
Backing up X X
Restoring X X
Disaster recovery planning X X

Monitoring X X
Performance tuning X X
Patching X X
Installing X X
Troubleshooting X X
Coding X X
Developing standards and best practices X X
Implementing security X X
Capacity planning X X
Managing projects X X
TABLE 1-2.
SQL Server and Oracle Skill Sets
The home page of Oracle Enterprise Manager, shown in Figure 1-1,
provides a quick look at the status of the database. It shows if the database
is up or down, a list of errors in the alert log, and general server information
about CPU and active sessions. Checking system-level resources, such as
CPU and memory usage, in a Microsoft Windows system is probably
already part of your SQL Server health check routine. Knowing that these
details are available in Oracle Enterprise Manager gives you a good place to
start. You’ll learn more about Oracle Enterprise Manager in Chapter 5.
If you have scripts created in Perl or another programming language to
monitor and manage SQL Server, these scripts can be leveraged to create
similar scripts for Oracle. Having such scripts is a great start.
8
Oracle Database Administration for Microsoft SQL Server DBAs
FIGURE 1-1.
Oracle Enterprise Manager home page
Database Migrations
You might need to learn Oracle because your company’s current database
will be converted from SQL Server to Oracle. There are various ways to

migrate, but all begin with a solid plan. The options available have varying
inputs and outputs, as well as varying amounts of downtime and risk.
You will need an Oracle database, a way to convert the definitions of
the tables from SQL Server datatypes to Oracle datatypes, a way to move
the data over to the new system, and a way to convert the stored procedures
and packages. Depending on how big and complex the database is, this
could be a very simple or a very complicated move.
Not all of the datatypes can translate exactly from one platform to
another. Table 1-3 shows just an example of some of the conversions.
Moving the data is probably the least of your concerns, unless you have
several terabytes of data to transfer. Data can be moved out of SQL Server
with the bcp utility, and then SQL*Loader can load it on the Oracle side.
SQL Server Integration Services (SSIS) packages can be created to export
from one database into the other.
Chapter 1: The Database Administrator
9
DBA Monitoring Checklist
DBAs typically monitor the following:
■
Backup jobs ran successfully (full and logs)
■
Space on server and tablespaces/data files
■
Errors in the alert log/server log
■
Any new information in the alert log/server log
■
Security auditing
■
Scheduled jobs ran successfully

■
Current statistics
The Oracle SQL Developer tool is available to assist with any of these
types of migrations, as shown in Figure 1-2. The Migration Wizard sets up a
repository for the work area of the conversion process. It pulls in the source
information, translates the structures to Oracle structures, and then allows
for movement of data online or offline, depending on how much data needs
to be transferred. The constraints, primary keys, foreign keys, and check
constraints are included in the migration process, and stored procedures are
translated into Oracle structures. If there are issues in converting a datatype,
you will get an error when attempting the migration process. (Oracle SQL
Developer is discussed in more detail in Chapter 5.)
NOTE
Oracle SQL Developer can be used to manage
SQL Server databases. Java Database
Connectivity (JDBC) drivers will need to be
configured with Oracle SQL Developer before
the SQL Server tab is present to connect to the
SQL Server database. Details on the procedure
are available from the Oracle SQL Developer
Help menu. Search for “database: third-party
JDBC drivers.”
Well, pulling the SQL Server database over into an Oracle database with
the provided tools sounds simple enough. Then the fun begins. Just because
10
Oracle Database Administration for Microsoft SQL Server DBAs
SQL Oracle
DATETIME DATE, TIMESTAMP
FLOAT NUMBER
VARCHAR VARCHAR2

CHAR CHAR
VARBINARY BLOB
NUMERIC NUMBER
TABLE 1-3.
Example Datatype Conversions
the SQL Server database is now available in Oracle doesn’t mean that all of
the indexes, statistics, and types of stored procedures are the best for use in
Oracle and will perform optimally. Testing and more testing are needed to
validate that the new structures and datatypes match those in the stored
procedures, tables, and views.
Validation of the data should include looking at the timestamps and
verifying that times as well as dates match up as needed. Indexes and
referential integrity need to be verified. The stored procedures need to be
checked to ensure they can return expected results. Jobs will need to be
scheduled using DBMS_SCHEDULER. Permissions need to be examined to
confirm that the security configured for access by the users is present.
As these pieces get validated for the application, you can look at the
areas that would benefit from different standards or from using some new
features in Oracle. You can see how you did it in SQL Server and consider
the best way to do it in Oracle. The rest of this book will help guide you
along that path.
Chapter 1: The Database Administrator
11
FIGURE 1-2.
Migration Wizard in Oracle SQL Developer