- The DBA: Revered or Reviled?
- Why Learn Database Administration?
- The Management Discipline of Database Administration
- Database, Data, and System Administration
- DBA Tasks
- Types of DBAs
- Staffing Considerations
- Multiplatform DBA Issues
- Test and Production
- New Technology and the DBA
- DBA Certification
- The Rest of the Book
- Review
This chapter is from the book
This chapter is from the book
This chapter is from the book
New Technology and the DBA
The DBA is at the center of the action whenever new ways of doing business and new technologies are introduced to the organization. Data is the lifeblood of modern business, data is housed by the database, and the DBA is the expert who understands database technology—and in particular, how databases can be integrated with other new technologies.
Let's examine three specific newer technologies that rely on database administration—at least somewhat—to be effectively implemented: database-coupled application logic, Internet-enabled e-business development, and handheld computing.
Procedural DBAs: Managing Database Logic
Until recently, the purpose of a database management system was, appropriately enough, to store, manage, and access data. Although these core capabilities are still required of modern DBMS products, additional procedural functionality is slowly becoming not just a nice feature to have, but a necessity. Features such as triggers, user-defined functions, and stored procedures provide the ability to define business rules to the DBMS instead of in separate application programs. These features couple application logic tightly to the database server.
Since all of the most popular RDBMS products provide sometimes-complex features to facilitate database-coupled procedural logic, additional management discipline is required to ensure the optimal use of these features. Typically, as new features are added, their administration, design, and management are assigned to the DBA by default. However, without proper planning and preparation, chaos can ensue. First let's examine how database logic is stored in a DBMS.
Stored Procedures
Stored procedures can be thought of as programs that live in a database. The procedural logic of a stored procedure is maintained, administered, and executed through the database commands. The primary reason for using stored procedures is to move application code from a client workstation to the database server. Stored procedures typically consume less overhead in a client/server environment because one client can invoke a stored procedure that causes multiple SQL statements to be run. The alternative, the client executing multiple SQL statements directly, increases network traffic and can degrade overall application performance.
A stored procedure is a freestanding database object; it is not "physically" associated with any other object in the database. A stored procedure can access and/or modify data in many tables.
Triggers
Triggers are event-driven specialized procedures that are attached to database tables. The trigger code is automatically executed by the RDBMS as data changes in the database. Each trigger is attached to a single, specified table. Triggers can be thought of as an advanced form of rule or constraint that uses procedural logic. A trigger cannot be directly called or executed; it is automatically executed (or "fired") by the RDBMS as the result of a SQL INSERT, UPDATE, or DELETE statement issued on its associated table. Once a trigger is created, it is always executed when its firing event occurs.
User-Defined Functions
A user-defined function (UDF) provides a result based on a set of input values. UDFs are programs that can be executed in place of standard, built-in SQL scalar or column functions. A scalar function transforms data for each row of a result set; a column function evaluates each value for a particular column in each row of the results set and returns a single value. Once written, and defined to the RDBMS, a UDF becomes available just like any other built-in database function.
Table 1-1 summarizes the differences between stored procedures, triggers, and UDFs.
Table 1-1 Procedural Database Objects
|
Object Type |
Definition |
Executed |
How |
|
Stored Procedure |
Program logic executed on the database server |
By request |
Explicit |
|
Triggers |
Event-driven procedures attached to database tables |
Automatically |
Implicit |
|
UDFs |
Program logic extending SQL functionality |
By request in SQL |
Explicit |
Administering Stored Procedures, Triggers, and UDFs
Once developers begin to rely on stored procedures, triggers, and UDFs, DBAs need to take steps to manage them properly. DBAs must grapple with the issues of quality, maintainability, efficiency, and availability. How and when will these procedural objects be tested? The impact of a failure is enterprisewide, increasing the visibility and criticality of these objects. Who is responsible if they fail? The answer must be—the DBA.
The role of administering procedural database logic should fall upon someone skilled in that discipline. A new type of DBA is required to accommodate the administration of database procedural logic. This new role can be defined as a procedural DBA.
The procedural DBA is responsible for those database management activities that require procedural logic support. He ensures that stored procedures, triggers, and user-defined functions are effectively planned, implemented, shared, and reused. The procedural DBA also takes primary responsibility for coding and testing all triggers. Stored procedures and user-defined functions, although likely to be coded by application programmers, should be reviewed for accuracy and performance by procedural DBAs. (See Figure 1-11.)
)
Figure 1-11 Procedural DBA duties
The procedural DBA leads the review and administration of all procedural database objects: triggers, stored procedures, and UDFs. Although the procedural DBA is unlikely to be as skilled at programming as an applications programmer or systems analyst, he must be able to write and review program code reasonably well. The skill level required depends on what languages are supported by the DBMS for creating procedural objects, the rate and level of adoption within the organization, and whether an internal organization exists for creating common, reusable programs. Table 1-2 provides a reasonable level of procedural DBA involvement for each type of procedural object. Additionally, the procedural DBA should be on call for any problems that occur with database procedural objects in production.
Table 1-2 Procedural DBA Involvement by Object
|
Object Type |
Level of Procedural DBA Involvement |
|
Stored Procedure |
Not likely to write stored procedures; must review all code before migration to production; communicates availability and promotes reuse. |
|
Triggers |
Likely to write, test, and debug triggers; communicates deployment of triggers to ensure application awareness. |
|
UDFs |
Not likely to write user-defined functions; works closely with the development team to ensure UDF functionality and performance; reviews all code before migration to production; communicates availability and promotes reuse. |
As shown in Figure 1-11, the procedural DBA requires communication skills as much as he requires technological acumen. In addition to managing and optimizing database procedural objects, the procedural DBA must inform the development community of new triggers, stored procedures, and UDFs. Furthermore, the DBA must promote reuse. If the programmers do not know that these objects exist, they will never be used.
Other procedural administrative functions can be allocated to the procedural DBA. Depending on the number of DBAs and the amount of application development needed, the procedural DBA can be assigned to additional functions such as the following:
Participating in application code design reviews
Reviewing and analyzing SQL access paths (from "EXPLAIN" or "SHOW PLAN")
Debugging SQL
Writing and analyzing complex SQL statements
Rewriting queries for optimal execution
Offloading coding-related tasks to the procedural DBA can help the other staff DBAs concentrate on the actual physical design and implementation of databases, resulting in much better designed databases. Procedural DBAs should have the same line of report as traditional DBAs to enable better sharing of skills between the groups. Of course, there will need to be a greater synergy between procedural DBAs and the application programmers. The procedural DBA should typically come from the application programming ranks because this is where the coding skill exists.
The Internet: From DBA to e-DBA
Companies of every size are using Internet technologies to speed up business processes. Indeed, e-business has evolved as a new term to describe the transformation of key business processes using Internet technologies. Modern organizations use the Web to communicate with their partners and customers, to connect with their back-end databases, and to conduct transactions (e-commerce). E-business is the integration of traditional information technology with the Internet. This integration creates a more nimble business, prepared for the trials and tribulations of conducting business in the 21st century.
E-businesses must be able to adapt and react to constant change. When a business is online, it never closes. People expect full functionality on Web sites they visit regardless of the time. And the Web is worldwide. It may be two o'clock in the morning in New York City, but it is always prime time somewhere in the world. An e-business must be available and prepared to engage with customers 24 hours a day, 365 days a year (366 during leap years). Failure to do so risks losing business. When a Web site is down, the customer will go elsewhere to do business because the competition is just a simple mouse-click away. Therefore, those who manage an e-business must be adept, proactive, and ever vigilant.
The frantic pace of an e-business makes extreme demands on those that keep it operational, and DBAs are much affected. The need to integrate the Web with traditional IT services, such as the DBMS, places high expectations on database administrators.
An e-DBA is a DBA who is capable of managing Web-based applications and their Internet-related issues. With all of the knowledge and training of a traditional DBA, the e-DBA adapts these skills to suit applications and databases that are Internet enabled. When the Web is coupled with traditional applications and databases, a complex infrastructure is the result. (See Figure 1-12.) The e-DBA must be capable of navigating this complex, heterogeneous infrastructure and providing expertise wherever databases interact within this infrastructure.
)
Figure 1-12 The complex infrastructure enabling Web-to-database capabilities
Many factors impact database administration when you couple the Internet with database technology. Some of these issues include
24/7 data availability
New technologies such as Java and XML
Web connectivity
Integration of legacy data with Web-based applications
Database and application architecture
Web-based administration
Performance engineering for the Internet
Unpredictable workload
The PDA DBA
Personal digital assistant devices, better known as PDAs, are fast becoming a necessity for modern executives and businessmen. A PDA is a handheld computing device. Whether your PDA of choice is a Palm Pilot or a PocketPC, your PDA may soon have a DBMS running on it. Why is that interesting? Does it change the way you will use your PDA? What will that mean to your IT department?
PDAs offer many benefits. The devices are small and therefore easily transportable. They enhance a mobile worker's ability to be mobile. However, challenges must be faced as organizations incorporate PDAs into their infrastructure. Companies with remote workers such as a distributed sales force or delivery tracking services will most likely be the first impacted. The data on the PDAs must be managed professionally to ensure integrity and reliability. Because the device is remote, sharing of data can be difficult. The data on the PDAs must be reliably synchronized with existing enterprise systems and databases.
All major DBMS vendors provide small-footprint versions of their flagship products to run on PDAs. For example, IBM markets DB2 Everyplace, Oracle sells Oracle8i Lite, and Sybase offers Adaptive Server Anywhere. The general idea is to store a small amount of critical data on the PDA in a database; the local PDA database is later synchronized to long-term data stores on enterprise database servers. Each PDA DBMS provides technology to synchronize data back and forth from the PDA to the enterprise server platforms.
A database the size of those stored on PDAs should not require the in-depth tuning and administration required of enterprise database implementations. However, DBAs will be called upon to help design appropriately implemented databases for small-form-factor devices like PDAs. However, the biggest impact on the DBA will be the necessity for managing data synchronization from hundreds or thousands of PDAs. When should synchronization be scheduled? How will it impact applications that use large production databases that are involved in the synchronization? How can you ensure that a mobile user will synchronize his data reliably and on schedule?
These are not trivial issues. The DBA staff must be ready to support the organization's inevitable request for this technology by understanding data synchronization technology and the need for remote database users at their organization. Pervasive computing and the mobile workplace are here to stay. The DBA staff must be ready to support these mobile workers with a valid, shared data infrastructure.
As new technology is introduced to the organization, the DBA group is typically the first to examine and use it. The preceding three technologies are merely examples of new trends and technologies that require database administration for efficient and effective implementation.