Whatever Happened to Object-Oriented Databases

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                                                                                                  are gaining in popularity and are ex-


     Whatever                                                                                     pected to outsell even relational data-
                                                                                                  bases by 2003. And OO databases (see
                                                                                                  the “OO Database Orientation” sidebar)
                                                                                                  are still minor players with solid but


     Happened to                                                                                  strictly niche markets. Sales of relational
                                                                                                  databases have grown considerably
                                                                                                  faster than the sales of OO databases,
                                                                                                  and annual worldwide RDBMS revenues


     Object-Oriented                                                                              are now about 50 times larger.
                                                                                                     Rick Cattell, distinguished engineer at
                                                                                                  Sun Microsystems, indicated, “Object-
                                                                                                  oriented databases are doing just fine, and


     Databases?                                                                                   the news of their demise is highly exag-
                                                                                                  gerated. While their market [share] isn’t
                                                                                                  as big, they continue to be used in areas
                                                                                                  like CAD (computer-aided design) and
     Neal Leavitt                                                                                 telecommunications, where RDBMSs are
                                                                                                  not well suited.”
                                                                                                     However, said Michael Stonebraker,




     A
                                                                                                  chief technology officer at Informix and
               couple of years ago, industry                                                      an ORDBMS proponent and pioneer,
               observers touted object-oriented                                                   “ODBMSs occupy a small niche market
               databases as a technology on the                                                   that has no broad appeal. The technology
               rise, well suited for the emerg-                                                   is in semi-rigor mortis, and ORDBMSs
               ing Internet age.                                                                  will corner the market within five years.”
       They said object-oriented database-
     management systems (ODBMSs) would                                                            DATABASE MARKETPLACE
     soon become the primary database tech-                                                          As Figure 1 shows, IDC, a market
     nology, supplanting relational database-                                                     research firm, reported global 1999 sales
     management systems (RDBMSs), which                                                           revenue of $11.1 billion for relational and
     were not designed to handle the type of                                                      object-relational databases, but only $211
     multimedia data frequently found on the                                                      million for OO databases. By 2001, IDC
     Internet. As further evidence of this, they                                                  expects these totals to increase to $15.6
     said the growth of intranets signaled a                                                      billion and $265 million, respectively.
     decline in the use of client-server net-      Relational databases are still by far the      Through 2004, IDC predicts annual
     works, on which most relational data-         most widely used databases. Meanwhile,         growth rates of 18.2 percent for relational
     bases were used.                              object-relational database-management          databases and only 12.5 percent for
       Fast-forward to today, and none of          systems (ORDBMSs) have added object            object-oriented databases. (These figures
     these predictions has come to pass.           capabilities to relational databases. They     are based on data IDC [http://www.idc.
                                                                                                  com] gathered through 5 May 2000 for
                                                                                                  Report No. 22542, “Enterprise Database
       Relating to Relational Databases                                                           Management Systems Market Forecast
         A relational database-management          examination from multiple perspectives.        and Analysis, 2000-2004.”)
      system (RDBMS) includes a collection            Relational databases are good for
      of data items organized as a table, with     managing large amounts of structured,          OO databases’ niche markets
      the columns representing data categories     alphanumerical data. For example, com-           OO databases have not become major
      and the rows representing the data itself.   panies use them to maintain records of         players in the database market. However,
      For example, a table might contain           transactions or personnel files.                they do have niche markets, said Larry
      information about product orders, with          However, relational databases are rigid     Alston, chief technology officer of
      the columns representing product types,      because their only data structure is tables.   exCelon (http://www.exceloncorp.com),
      customers, dates of sale, and prices.        And they work only with limited, simple        a provider of e-commerce products and
         Users can access data in the order in     data types, such as integers, and thus have    services, including OO databases.
      which it was entered in a table or           had trouble handling complex and user-           Because OO databases handle complex
      reassemble it in many different ways for     defined data types, including multimedia.       objects particularly well, they can manage
                                                                                                  complex data relationships effectively,

16               Computer
 OO Database Orientation
    An OO database-management system           City University in London. With a rela-          housing and business-intelligence services
 (ODBMS) supports the modeling and             tional database, he said, you have to de-        for the Hurwitz Group consultancy.
 creation of data as objects. Users can        compose the aircraft into tables and then           For this and other reasons, although
 support new media types with OO data-         join the tables when you need to recon-          OO databases excel at handling some
 bases simply by creating new objects.         struct the aircraft.                             data types, they have not become major
    With OO databases, the application            However, OO databases don’t scale up          players in the database market.
 and the database use exactly the same         to high transaction volumes and user                Figure A illustrates the type of archi-
 object model. This isn’t the case with        counts as well as relational databases, said     tecture used in an OO database—in this
 relational databases, with which users        Philip Russom, director of data ware-            case, Objectivity’s distributed ODBMS.
 must utilize an object model for the
 application and a relational-data model
 for the database. Users thus must                                    Client application
 develop mapping procedures between
 the object and relational models.                                                                                                Page
                                                                      Language interface                                         server
    RDBMS programmers sometimes spend                        (C, C++, Java, Smalltalk, and SQL++)
 more than 25 percent of their coding time
 mapping program objects to the database,                                                                                Disk
                                                        Query               Object             Schema                  storage
 said Carl Olofson, program director of                manager             manager             manager
 information and data management soft-
 ware for IDC, a market research firm.
                                                                                                                                  Page
    “The result for ODMBSs is less code                                                       Transaction                        server
                                                                              Cache
 to develop, reduced development time,                                                         manager
 and reduced maintenance costs,” said
                                                                                                                         Disk
 Doug Barry, executive director of Barry                                                                               storage
 & Associates consultants and also chair                Event              Storage             Network
                                                       manager             manager             manager
 and executive director of the Object Data
 Management Group (ODMG), an OO                                                                                                    Lock
 database-standards organization.                                           Posix                                                 server
    Meanwhile, OO databases are well
                                                                                                                      Source: Objectivity
 suited for use with applications that must
 manage complex relationships among
 data objects.                                 Figure A. Objectivity’s distributed database demonstrates important differences between
    “If you’re modeling a Boeing 747 with      relational and OO databases. For example, unlike relational databases, Objectivity’s
 an ODBMS, the relationships between           database requires an object manager, which directly creates, names, and manipulates
 aircraft parts are directly managed [by the   objects as required by the client application. Also, Objectivity’s storage manager can handle
 database],” said Akmal Chaudhri, a data-      clusters of objects of varying sizes. Relational databases’ storage managers are built like
 base expert and visiting scholar at The       spreadsheets and tend to work best with data elements of similar size and structure.



said Leon Guzenda, chief technology offi-          “Companies in London like J.P. Mor-            instruments quickly and easily, which
cer of ODBMS vendor Objectivity.               gan, Chase [Manhattan], and Citibank              helps companies get these products to
   OO databases are thus popular for use       are using ODBMS technologies in mod-              market quickly.
with artificial intelligence and CAD/CAM        eling financial instruments [such as
(computer-aided design and manufactur-         derivatives and bonds],” said Akmal               Technical issues
ing) applications, which entail complex        Chaudhri, a database expert and visit-               Several technical issues have led to OO
data relationships, he said. CAD/CAM           ing scholar at The City University in             databases’ limited strength in the data-
applications also use multimedia data          London.                                           base marketplace.
types, which OO databases work with               The companies use object-oriented                 Object-relational databases. RDBMS
effectively.                                   analysis and design to model these prod-          vendors began developing and market-
   Meanwhile, Sun’s Cattell said, hospital     ucts because object orientation helps             ing OR databases in part in response to
patient-care tracking systems use OO           effectively capture the instruments’ struc-       the perceived threat from OO databases.
databases because they are easier for          ture and behavior, Chaudhri said. Object             OR databases work via an object layer
medical personnel to work with than            orientation also provides mechanisms              that sits atop a conventional tabular rela-
relational databases.                          such as inheritance for modeling new              tional engine. Vendors integrate OO fea-

                                                                                                                       August 2000             17
I n d u s t r y Tr e n d s




                                       30,000

                                                  Object-oriented
                                                   databases
                                                  Miscellaneous pre- and
                                                   post-relational databases
                                       25,000     Relational and object-
                                                   relational databases




    Revenue (millions of US dollars)
                                       20,000




                                       15,000




                                       10,000




                                        5,000




                                           0
                                                1999    2000     2001      2002   2003    2004
                                                                                  Source: IDC, 2000



Figure 1. IDC, a market research firm, predicts steady growth for
object-oriented databases and for relational and object-relational data-
bases through 2004. However, IDC predicts that relational and object-
relational databases will continue to dominate the market.

tures into the databases via software modules (such as
Informix’s DataBlades or Oracle’s Cartridges), each designed to
handle video, audio, text, or other types of media. So, in addi-
tion to handling the numerical data generally used in relational
databases, OR databases can handle multimedia data types.
   Performance. OO databases can store data sets in their entirety
and thus typically run faster than relational databases, which
must break data sets into parts for storage within tables and then
reassemble them in response to queries.
   In addition, said Sun’s Cattell, OO databases can automatically
cache data in the client application’s memory, thereby eliminating
extra calls to the DBMS’s back end and speeding up responses.
   And OO databases use optimizers that determine the best way
to use a database’s indices and physical layout to satisfy a query.
   However, relational databases have reduced OO databases’
performance advantage with improved optimizers. The opti-
mizers improve ways of finding information within relational
databases’ tables and indices.
   Standardization. Relational databases use the long-established
SQL (Structured Query Language) standard, which has been
adopted by the International Organization for Standardization
(ISO) and the American National Standards Institute (ANSI).
SQL, used for querying and updating a relational database,
serves as a user interface and application    Business issues                                     urtwitz’s Russom thinks OO data-
program interface to an RDBMS.
   The Object Database Management
Group has developed ODMG standards
                                                 “OO systems have not focused on
                                              bread-and-butter traditional business-
                                              data processing applications where
                                                                                            H     bases will continue to be used mostly
                                                                                                  in niche markets and that their adop-
                                                                                            tion has peaked. “With this impending
for object-database and object-relational-    high performance, reliability, and scal-      downturn in the ODBMS life cycle, many
mapping products since 1993.                  ability are crucial,” Stonebraker said.       ODBMS vendors are scrambling to de-
   However, the Object Database Manage-       “This is a large market where relational      velop new products or repositioning exist-
ment Group hasn’t promoted ODMG               systems excel and have enjoyed wide           ing offerings to create new revenue sources
widely within the ODBMS community and         adoption.”                                    as revenue from ODBMSs’ slow down.”
needs more vendors on board to make the          “Companies are justifiably loathe to           “Relational vendors realized that
standard an important factor in the indus-    scrap such systems for a different tech-      objects are important and added them,
try, said Philip Russom, director of data     nology, unless it offers a compelling busi-   producing OR systems,” Stonebraker
warehousing and business-intelligence ser-    ness advantage, which has rarely been         said. “However, the failure of OO ven-
vices for the Hurwitz Group consultancy.      demonstrated by OO systems,” he said.         dors to realize the importance of SQL
   For example, he said, the group cre-       “As such, relational systems and their OR     and the needs of business-data process-
ated an OQL (Object Query Language)           descendants continue to be the market         ing has hurt them immensely.” ✸
standard, but very few database vendors       leaders.”
implemented it.                                  Meanwhile, because relational data-        Neal Leavitt is president of Leavitt
   “A much bigger problem is that the         bases have a much bigger installed base,      Communications. Contact him at neal@
vendors behind ODMG represent zero            RDBMS vendors have more money and             leavcom.com.
billion [dollars] in revenue while the ven-   marketing clout than ODBMS vendors.
dors behind SQL . . . represent several          And with their bigger installed base,       Editor: Lee Garber, Computer, 10662 Los
billion in revenue,” said Informix’s          more tools are available for relational        Vaqueros Circle, PO Box 3014, Los Alamitos,
Stonebraker. “Hence, it is not a standard     databases, for such functions as admin-        CA 90720-1314; l.garber@computer.org
with critical mass in the marketplace.”       istration and Web development.