|
EJB QL
EJB QL or EJB-QL is a portable database query language for Enterprise Java Beans. It was used in Java EE applications. Compared to SQL, however, it is less complex but less powerful as well. History The language has been inspired, especially EJB3-QL, by the native Hibernate Query Language HQL. In EJB3 It has been mostly replaced by the Java Persistence Query Language The Jakarta Persistence Query Language (JPQL; formerly Java Persistence Query Language) is a platform-independent object-oriented query language defined as part of the Jakarta Persistence (JPA; formerly Java Persistence API) specification. JPQL i .... Differences EJB QL is a database query language similar to SQL. The used queries are somewhat different from relational SQL, as it uses a so-called "abstract schema" of the enterprise beans instead of the relational model. In other words, EJB QL queries do not use tables and their components, but enterprise beans, their persistent state, and their relationships. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance. A database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Query Language
Query languages, data query languages or database query languages (DQL) are computer languages used to make queries in databases and information systems. A well known example is the Structured Query Language (SQL). Types Broadly, query languages can be classified according to whether they are database query languages or information retrieval query languages. The difference is that a database query language attempts to give factual answers to factual questions, while an information retrieval query language attempts to find documents containing information that is relevant to an area of inquiry. Other types of query languages include: * Full-text. The simplest query language is treating all terms as bag of words that are to be matched with the postings in the inverted index and where subsequently ranking models are applied to retrieve the most relevant documents. Only tokens are defined in the CFG. Web search engines often use this approach. * Boolean. A query language that also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterprise Java Beans
Jakarta Enterprise Beans (EJB; formerly Enterprise JavaBeans) is one of several Java APIs for modular construction of enterprise software. EJB is a server-side software component that encapsulates business logic of an application. An EJB web container provides a runtime environment for web related software components, including computer security, Java servlet lifecycle management, transaction processing, and other web services. The EJB specification is a subset of the Java EE specification. Specification The EJB specification was originally developed in 1997 by IBM and later adopted by Sun Microsystems (EJB 1.0 and 1.1) in 1999 and enhanced under the Java Community Process aJSR 19(EJB 2.0)JSR 153(EJB 2.1)JSR 220(EJB 3.0)JSR 318(EJB 3.1) anJSR 345(EJB 3.2). The EJB specification provides a standard way to implement the server-side (also called " back-end") 'business' software typically found in enterprise applications (as opposed to 'front-end' user interface software). Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java EE
Jakarta EE, formerly Java Platform, Enterprise Edition (Java EE) and Java 2 Platform, Enterprise Edition (J2EE), is a set of specifications, extending Java SE with specifications for enterprise features such as distributed computing and web services. Jakarta EE applications are run on reference runtimes, that can be microservices or application servers, which handle transactions, security, scalability, concurrency and management of the components it is deploying. Jakarta EE is defined by its specification. The specification defines APIs (application programming interface) and their interactions. As with other Java Community Process specifications, providers must meet certain conformance requirements in order to declare their products as ''Jakarta EE compliant''. Examples of contexts in which Jakarta EE referencing runtimes are used are: e-commerce, accounting, banking information systems. History The platform was known as ''Java 2 Platform, Enterprise Edition'' or ''J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Persistence Query Language
The Jakarta Persistence Query Language (JPQL; formerly Java Persistence Query Language) is a platform-independent object-oriented query language defined as part of the Jakarta Persistence (JPA; formerly Java Persistence API) specification. JPQL is used to make queries against entities stored in a relational database. It is heavily inspired by SQL, and its queries resemble SQL queries in syntax, but operate against JPA entity objects rather than directly with database tables. In addition to retrieving objects (SELECT queries), JPQL supports set based UPDATE and DELETE queries. Examples Example JPA Classes, getters and setters omitted for simplicity. @Entity public class Author @Entity public class Book @Entity public class Publisher Then a simple query to retrieve the list of all authors, ordered alphabetically, would be: SELECT a FROM Author a ORDER BY a.firstName, a.lastName To retrieve the list of authors that have ever been published by XYZ Press: SELECT DIS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Container-Managed Persistence
Jakarta Enterprise Beans (EJB; formerly Enterprise JavaBeans) is one of several Java APIs for modular construction of enterprise software. EJB is a server-side software component that encapsulates business logic of an application. An EJB web container provides a runtime environment for web related software components, including computer security, Java servlet lifecycle management, transaction processing, and other web services. The EJB specification is a subset of the Java EE specification. Specification The EJB specification was originally developed in 1997 by IBM and later adopted by Sun Microsystems (EJB 1.0 and 1.1) in 1999 and enhanced under the Java Community Process aJSR 19(EJB 2.0)JSR 153(EJB 2.1)JSR 220(EJB 3.0)JSR 318(EJB 3.1) anJSR 345(EJB 3.2). The EJB specification provides a standard way to implement the server-side (also called " back-end") 'business' software typically found in enterprise applications (as opposed to 'front-end' user interface software). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information Science
Information science (also known as information studies) is an academic field which is primarily concerned with analysis, collection, classification, manipulation, storage, retrieval, movement, dissemination, and protection of information. Practitioners within and outside the field study the application and the usage of knowledge in organizations in addition to the interaction between people, organizations, and any existing information systems with the aim of creating, replacing, improving, or understanding the information systems. Historically, information science (informatics) is associated with computer science, data science, psychology, technology, library science, healthcare, and intelligence agencies. However, information science also incorporates aspects of diverse fields such as archival science, cognitive science, commerce, law, linguistics, museology, management, mathematics, philosophy, public policy, and social sciences. Foundations Scope and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
