Объект-реляциялық дерекқор бетінің бастапқы мәтінін қарау

'''Объект-реляциялық дерекқор''' ({{lang-en|object-relational database}}, қысқаша: '''ORD'''), '''object-relational database management system''' ('''ORDBMS'''), реляциялық дерекқорға ұқсас дерекқор басқару жүйесі, айырмашылығы объектке-бағытталған дерекқор моделі бар: объекттер, класстар және мұрагерлік дерекқор схемасында және сұрату тілінде тікелей іске асырылған.

<!--is a [[database management system]] (DBMS) similar to a [[relational database]], but with an [[object-oriented]] database model: objects, classes and inheritance are directly supported in [[database schema]]s and in the [[query language]].  In addition, just as with proper relational systems, it supports extension of the [[data model]] with custom [[data type|data-type]]s and [[method (computer science) |method]]s.
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[[File:Object-Oriented Model.svg|thumb|320px|Объект-реляциялық дерекқор моделінің мысалы.<ref name="USDT01">{{Citation | url = http://knowledge.fhwa.dot.gov/tam/aashto.nsf/All+Documents/4825476B2B5C687285256B1F00544258/$FILE/DIGloss.pdf | title = Data Integration Glossary | place = US | publisher = Department of Transportation | month = August | year = 2001}}{{dead link|date=шілде 2012}}</ref>]]
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An object-relational database can be said to provide a middle ground between relational databases and ''object-oriented databases'' ([[OODBMS]]). In object-relational databases, the approach is essentially that of relational databases: the data resides in the database and is manipulated collectively with queries in a query language; at the other extreme are OODBMSes in which the database is essentially a persistent object store for software written in an [[object-oriented programming language]], with a programming [[API]] for storing and retrieving objects, and little or no specific support for querying.

== Overview ==
The basic goal for the Object-relational database is to bridge the gap between relational databases and the object-oriented modeling techniques used in programming languages such as [[Java (programming language)|Java]], [[C++]], [[Visual Basic .NET]] or [[C Sharp (programming language)|C#]].  However, a more popular alternative for achieving such a bridge is to use a standard relational database systems with some form of [[Object-relational mapping | Object-relational mapping (ORM)]] software.  Whereas traditional [[RDBMS]] or SQL-DBMS products focused on the efficient management of data drawn from a limited set of data-types (defined by the relevant language standards), an object-relational DBMS allows software developers to integrate their own types and the methods that apply to them into the DBMS.

The ORDBMS (like [[ODBMS]] or [[OODBMS]]) is integrated with an [[object-oriented programming language]].  The characteristic properties of ORDBMS are 1) complex data, 2) type inheritance, and 3) object behavior. '''Complex data''' creation in most SQL ORDBMSs is based on preliminary schema definition via the [[user-defined type]] (UDT). Hierarchy within structured complex data offers an additional property, '''type inheritance'''.  That is, a structured type can have subtypes that reuse all of its attributes and contain additional attributes specific to the subtype. Another advantage, the '''object behavior''', is related with access to the program objects. Such program objects have to be storable and transportable for database processing, therefore they usually are named as persistent objects.  Inside a database, all the relations with a persistent program object are relations with its [[Object identifier|object identifier (OID)]].  All of these points can be addressed in a proper relational system, although the SQL standard and its implementations impose arbitrary restrictions and additional complexity<ref>{{Citation | last1 = Date | first1 = Christopher ‘Chris’ J | author1-link = Chris J Date | last2 = Darwen | first2 = Hugh | author2-link = Hugh Darwen | title = The Third Manifesto}}</ref>{{Rp | needed = yes|date=March 2012}}

In [[object-oriented programming|object-oriented programming (OOP)]] object behavior is described through the methods (object functions). The methods denoted by one name are distinguished by the type of their parameters and type of objects for which they attached ([[method signature]]). The OOP languages call this the [[Polymorphism in object-oriented programming|polymorphism]] principle, which briefly is defined as "one interface, many implementations". Other OOP principles, [[Inheritance (object-oriented programming)|inheritance]] and [[Encapsulation (object-oriented programming)|encapsulation]] are related both, with methods and attributes.  Method inheritance is included in type inheritance.  Encapsulation in OOP is a visibility degree declared, for example, through the PUBLIC, PRIVATE and PROTECTED modifiers.

== History ==
Object-relational database management systems grew out of research that occurred in the early 1990s. That research extended existing relational database concepts by adding [[object (computer science)|object]] concepts. The researchers aimed to retain a declarative query-language based on [[Predicate logic|predicate calculus]] as a central component of the architecture. Probably the most notable research project, Postgres (UC Berkeley), spawned two products tracing their lineage to that research: [[Illustra]] and [[PostgreSQL]].

In the mid-1990s, early commercial products appeared. These included Illustra<ref name="stonebraker">Stonebraker,. Michael with Moore, Dorothy. ''Object-Relational DBMSs: The Next Great Wave''. Morgan Kaufmann Publishers, 1996. ISBN 1-55860-397-2.</ref> (Illustra Information Systems, acquired by [[IBM Informix#1980: Early history|Informix Software]] which was in turn acquired by [[International Business Machines|IBM]]), [[Omniscience (database)|Omniscience]] (Omniscience Corporation, acquired by [[Oracle Corporation]] and became the original Oracle Lite), and [[UniSQL]] (UniSQL, Inc., acquired by [[KCOMS]]).  Ukrainian developer Ruslan Zasukhin, founder of [[Paradigma Software|Paradigma Software, Inc.]], developed and shipped the first version of [[Valentina (Database)|Valentina database]] in the mid-1990s as a [[C++]] [[Software development kit|SDK]].  By the next decade, PostgreSQL had become a commercially viable database and is the basis for several products today which maintain its ORDBMS features.

Computer scientists came to refer to these products as "object-relational database management systems" or ORDBMSs.<ref name="term">There was, at the time, a dispute whether the term was coined by [[Michael Stonebraker]] of Illustra or [[Won Kim]] of UniSQL.</ref>

Many of the ideas of early object-relational database efforts have largely become incorporated into [[SQL|SQL:1999]] via [[structured type]]s. In fact, any product that adheres to the object-oriented aspects of SQL:1999 could be described as an object-relational database management product. For example, IBM's [[IBM DB2|DB2]], [[Oracle database]], and [[Microsoft SQL Server]], make claims to support this technology and do so with varying degrees of success.

== Comparison to RDBMS ==
An RDBMS might commonly involve [[SQL]] statements such as these:
<source lang="sql">
   CREATE TABLE Customers  (
       Id          CHAR(12)    NOT NULL PRIMARY KEY,
       Surname     VARCHAR(32) NOT NULL,
       FirstName   VARCHAR(32) NOT NULL,
       DOB         DATE        NOT NULL
    );
    SELECT InitCap(Surname) || ', ' || InitCap(FirstName)
      FROM Customers
     WHERE Month(DOB) = Month(getdate())
       AND Day(DOB) = Day(getdate())
</source>
Most {{As of|2007|alt=current}} SQL databases allow the crafting of custom [[function (computer science)|function]]s, which would allow the query to appear as:
<source lang="sql">
    SELECT Formal(Id)
      FROM Customers
     WHERE Birthday(Id) = Today()
</source>
NOTE: Rather than fix this, only to have it unfixed '''yet''' again, let it stand as an example. The first SQL SELECT statement quoted above is both non-standard, and wrong. InitCap() isn't SQL-92 (or SQL-3), and the query's logic misses Customers born on a leap-day (171,000 United States citizens) for three years out of four.

In an object-relational database, one might see something like this, with user-defined data-types and expressions such as <code>BirthDay()</code>:
<source lang="sql">
    CREATE TABLE Customers (
      Id           Cust_Id     NOT NULL  PRIMARY KEY,
      Name         PersonName  NOT NULL,
      DOB          DATE        NOT NULL
    );
    SELECT Formal( C.Id )
      FROM Customers C
     WHERE BirthDay ( C.DOB ) = TODAY;
</source>
The object-relational model can offer another advantage in that the database can make use of the relationships between data to easily collect related records. In an [[address book]] application, an additional table would be added to the ones above to hold zero or more addresses for each user. Using a traditional RDBMS, collecting information for both the user and their address requires a "join":
<source lang="sql">
     SELECT InitCap(C.Surname) || ', ' || InitCap(C.FirstName), A.city
       FROM Customers C join Addresses A ON A.Cust_Id=C.Id -- the join
      WHERE A.city="New York"
</source>
The same query in an object-relational database appears more simply:
<source lang="sql">
    SELECT Formal( C.Name )
      FROM Customers C
     WHERE C.address.city="New York" -- the linkage is 'understood' by the ORDB
</source>
-->
== RDBMS-пен салыстыру ==
RDBMS жүйесі [[SQL]] коммандаларын төмендегідей қолданады:
<source lang="sql">
   CREATE TABLE Customers  (
       Id          CHAR(12)    NOT NULL PRIMARY KEY,
       Surname     VARCHAR(32) NOT NULL,
       FirstName   VARCHAR(32) NOT NULL,
       DOB         DATE        NOT NULL
    );
    SELECT InitCap(Surname) || ', ' || InitCap(FirstName)
      FROM Customers
     WHERE Month(DOB) = Month(getdate())
       AND Day(DOB) = Day(getdate())
</source>

== Тағы қараңыз ==
* [[SQL]]
* List of object-relational database management systems
* Объект дереқор
* Объект-реляциялық теңеу
* Реляциялық модель
* LINQ
* ADO.NET Entity Framework

== Сілттемелер ==
{{reflist}}

== Сыртқы сілттемелер ==

* {{Citation | url = http://savtechno.com/articles/ViewOfORDBMS.html | title = A Point of View on ORDBMS | first = Sergey | last = Savushkin | year = 2003 | accessdate = 2012-07-21}}.
* {{Citation | url = http://www.jpab.org/ | title = JPA Performance Benchmark}} — comparison of Java JPA ORM Products (Hibernate, EclipseLink, OpenJPA, DataNucleus).
* {{Citation | url = http://www.polepos.org/ | title = PolePosition Benchmark}} — shows the performance trade-offs for solutions in the [[object-relational impedance mismatch]] context.

{{Дерекқор}}

{{DEFAULTSORT:Object-Relational Database}}
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