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Object–relational Mapping
Object–relational mapping (ORM, O/RM, and O/R mapping tool) in computer science is a programming technique for converting data between type systems using object-oriented programming languages. This creates, in effect, a "virtual object database" that can be used from within the programming language. There are both free and commercial packages available that perform object–relational mapping, although some programmers opt to construct their own ORM tools. In object-oriented programming, data-management tasks act on objects that are almost always non- scalar values. For example, consider an address book entry that represents a single person along with zero or more phone numbers and zero or more addresses. This could be modeled in an object-oriented implementation by a "Person object" with an attribute/field to hold each data item that the entry comprises: the person's name, a list of phone numbers, and a list of addresses. The list of phone numbers would itself contain "Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (including the design and implementation of hardware and software). Computer science is generally considered an area of academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing security vulnerabilities. Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of repositories o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Document-oriented Database
A document-oriented database, or document store, is a computer program and data storage system designed for storing, retrieving and managing document-oriented information, also known as semi-structured data. Document-oriented databases are one of the main categories of NoSQL databases, and the popularity of the term "document-oriented database" has grown with the use of the term NoSQL itself. XML databases are a subclass of document-oriented databases that are optimized to work with XML documents. Graph databases are similar, but add another layer, the ''relationship'', which allows them to link documents for rapid traversal. Document-oriented databases are inherently a subclass of the key-value store, another NoSQL database concept. The difference lies in the way the data is processed; in a key-value store, the data is considered to be inherently opaque to the database, whereas a document-oriented system relies on internal structure in the ''document'' in order to extract met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object–relational Impedance Mismatch
The object–relational impedance mismatch is a set of conceptual and technical difficulties that are often encountered when a relational database management system (RDBMS) is being served by an application program (or multiple application programs) written in an object-oriented programming language or style, particularly because objects or class definitions must be mapped to database tables defined by a relational schema. The term ''object–relational impedance mismatch'' is derived from the electrical engineering term ''impedance matching''. Mismatches Objects (instances) reference one another and therefore form a directed graph in the mathematical sense (a network including loops and cycles). Relational schemas are, in contrast, tabular and based on relational algebra, which defines linked heterogeneous tuples (groupings of data fields into a "row" with different types for each field), where links are always reversible (foreign keys can be followed backwards, as INNER JOI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object–relational Database
An object–relational database (ORD), or object–relational database management system (ORDBMS), 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 schemas and in the query language. In addition, just as with pure relational systems, it supports extension of the data model with custom data types and methods. An object–relational database can be said to provide a middle ground between relational databases and object-oriented databases. 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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Persistence
An object database or object-oriented database is a database management system in which information is represented in the form of objects as used in object-oriented programming. Object databases are different from relational databases which are table-oriented. A third type, object–relational databases, is a hybrid of both approaches. Object databases have been considered since the early 1980s. Overview Object-oriented database management systems (OODBMSs) also called ODBMS (Object Database Management System) combine database capabilities with object-oriented programming language capabilities. OODBMSs allow object-oriented programmers to develop the product, store them as objects, and replicate or modify existing objects to make new objects within the OODBMS. Because the database is integrated with the programming language, the programmer can maintain consistency within one environment, in that both the OODBMS and the programming language will use the same model of representat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Database
An object database or object-oriented database is a database management system in which information is represented in the form of objects as used in object-oriented programming. Object databases are different from relational databases which are table-oriented. A third type, object–relational databases, is a hybrid of both approaches. Object databases have been considered since the early 1980s. Overview Object-oriented database management systems (OODBMSs) also called ODBMS (Object Database Management System) combine database capabilities with object-oriented programming language capabilities. OODBMSs allow object-oriented programmers to develop the product, store them as objects, and replicate or modify existing objects to make new objects within the OODBMS. Because the database is integrated with the programming language, the programmer can maintain consistency within one environment, in that both the OODBMS and the programming language will use the same model of represe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Object Request Broker Architecture
The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between systems on different operating systems, programming languages, and computing hardware. CORBA uses an object-oriented model although the systems that use the CORBA do not have to be object-oriented. CORBA is an example of the distributed object paradigm. Overview CORBA enables communication between software written in different languages and running on different computers. Implementation details from specific operating systems, programming languages, and hardware platforms are all removed from the responsibility of developers who use CORBA. CORBA normalizes the method-call semantics between application objects residing either in the same address-space (application) or in remote address-spaces (same host, or remote host on a network). Versi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AutoFetch
AutoFetch in computing is a mechanism for automatically tuning object-relational mapping queries. Ali Ibrahim and William Cook at the University of Texas at Austin developed the idea of "AutoFetch" including an implementation foHibernateand followed later by an implementation in Ebean. Benefits Improving the modularity of application code AutoFetch uses the program state (typically the call stack) to classify queries. This means that AutoFetch can tune the same query depending on HOW it was called. For example, a Data Access API such as findCustomer(int customerId) can be tuned differently depending on the callers of the method. Reducing the development and maintenance burden from Developers Because AutoFetch automatically gathers the profiling information developers do not need to manually try and gather this information and apply performance optimizations to the code. AutoFetch can monitor the object graph usage so that if the usage changes the tuning of the query ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Object–relational Mapping Software
This table shows a comparison of notable and available ORM software products. See also * List of object–relational mapping software * Object–relational mapping References External links ormeter.net.NET LINQ Language Integrated Query (LINQ, pronounced "link") is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages, originally released as a major part of .NET Framework 3.5 in 2007. LINQ extends the langu ... ORM Comparison – Updated 30 July 2010 {{DEFAULTSORT:Comparison of object-relational mapping software Object–relational mapping Object-relational mapping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Object–relational Mapping Software
This is a list of well-known object–relational mapping software. It is not up-to-date or all-inclusive. Java *Apache Cayenne, open-source for Java *Apache OpenJPA, open-source for Java * DataNucleus, open-source JDO and JPA implementation (formerly known as JPOX) * Ebean, open-source ORM framework *EclipseLink, Eclipse persistence platform * Enterprise JavaBeans (EJB) * Enterprise Objects Framework, Mac OS X/Java, part of Apple WebObjects * Hibernate, open-source ORM framework, widely used *Java Data Objects (JDO) * JOOQ Object Oriented Querying (jOOQ) *Kodo, commercial implementation of both Java Data Objects and Java Persistence API *TopLink by Oracle iOS *Core Data by Apple for Mac OS X and iOS .NET * Base One Foundation Component Library, free or commercial * Dapper, open source *Entity Framework, included in .NET Framework 3.5 SP1 and above *iBATIS, free open source, maintained by ASF but now inactive. *LINQ to SQL, included in .NET Framework 3.5 *NHibernate, open source ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Access Object
In software, a data access object (DAO) is a pattern that provides an abstract interface to some type of database or other persistence mechanism. By mapping application calls to the persistence layer, the DAO provides data operations without exposing database details. This isolation supports the single responsibility principle. It separates the data access the application needs, in terms of domain-specific objects and data types (the DAO's public interface), from how these needs can be satisfied with a specific DBMS (the implementation of the DAO). Although this design pattern is applicable to most programming languages, most software with persistence needs, and most databases, it is traditionally associated with Java EE applications and with relational databases (accessed via the JDBC API because of its origin in Sun Microsystems' best practice guidelines "Core J2EE Patterns". Advantages The primary advantage of using data access objects is the rigorous separation between two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object–relational Impedance Mismatch
The object–relational impedance mismatch is a set of conceptual and technical difficulties that are often encountered when a relational database management system (RDBMS) is being served by an application program (or multiple application programs) written in an object-oriented programming language or style, particularly because objects or class definitions must be mapped to database tables defined by a relational schema. The term ''object–relational impedance mismatch'' is derived from the electrical engineering term ''impedance matching''. Mismatches Objects (instances) reference one another and therefore form a directed graph in the mathematical sense (a network including loops and cycles). Relational schemas are, in contrast, tabular and based on relational algebra, which defines linked heterogeneous tuples (groupings of data fields into a "row" with different types for each field), where links are always reversible (foreign keys can be followed backwards, as INNER JOI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
