Release 2 (9.0.3)
Part Number B10061-01
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| Oracle9iAS TopLink Getting Started Release 2 (9.0.3) Part Number B10061-01 |
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This glossary contains terms and abbreviations that you should be familiar with when using TopLink.
The specification of how a programmer writing an application accesses the behavior and state of classes and objects. A set of classes that define services for a programmer.
A program whose sole purpose is to provide services to other programs called clients
A variable of a class or object. In TopLink, attribute describes all instance variables of a class. Every attribute contains a single mapping.
A reusable software component that can be combined to create an application. Usually, beans are bundled up with their corresponding BeanInfo classes into .jar files.
See also JAR.
The implementation of the bean. The bean is accessed from the client using the home and remote interfaces.
See also home interface and remote interface.
Bean-Managed Persistence, the bean developer is responsible for storing and retrieving the entity bean.
Compare to CMP.
Has a persistent superclass and also has subclasses. By default, queries performed on the branch class return instances of the branch class and any of its subclasses. However, the branch class can be configured so that queries on it return only instances of itself without instances of its subclasses.
Compare to leaf class and root class.
A category of objects. Classes allow data and method to be grouped together.
A field in the table of the root class that indicates which subclass should be instantiated
The search path that Java uses to locate class files on a hard drive
Container-Managed Persistence, the container is responsible for storing and retrieving the entity bean.
Compare to BMP.
Platform-independent technique for programs running on different machines to communicate with each other by creating contracts between objects for implementation as distributed applications.
Refers to any non-TopLink-generated SQL used through TopLink. This includes hard-coded SQL and stored procedure calls.
The data definition part of the structured query language (SQL). TopLink Mapping Workbench can generate DDL creation scripts that can be used to create tables on the desired database.
A large collection of data organized for rapid search and retrieval.
Location where non-bean classes are specified. TopLink requires that the bean classes be included here since they are referenced by the project.
Provides information required by the server to deploy the bean. An "EJB deployment descriptor" is not the same as a "TopLink descriptor."
See also descriptors.
A TopLink object that describes how an object's attributes and relationships are to be represented in relational database table(s). A "TopLink descriptor" is not the same as an "EJB deployment descriptor", although it plays a similar role.
A TopLink Mapping Workbench feature used for creating descriptors and mappings.
By default, TopLink accesses public attributes directly when writing the attributes of the object to the database or reading the attributes of the object from the database.
Compare to method access.
There are two basic ways of storing object attributes directly in a table:
TopLink provides five classes of direct mappings.
Compare to relationship mapping.
The TopLink equivalent of an SQL conditional clause. TopLink expressions are specified using the Expression and ExpressionBuilder classes.
A piece of information in a database table record.
A field or combination of fields that identify records in another table. Foreign keys are used to represent the relationships between records in different tables.
See also target foreign key.
A standard Java interface that extends javax.ejb.EJBHome. The home interface is accessed using JNDI and is used to create, find, and remove beans.
Used to cache objects for performance and to maintain object identity.
See also object identity.
A relationship in which the source and target are public objects that exist independently; the destruction of one object does not necessarily imply the destruction of the other.
Compare to private relationship.
An indirection object is one that acts as a stand-in for another object. In TopLink, indirection is implemented through Value Holders, which delay database access through acting as stand-in for any object relationships.
Describes how a child class inherits the characteristics of its parent class. TopLink supports multiple approaches to database implementations that preserve the inheritance relationship.
A Java term for creating an instance of a class.
Java archive, a file format used to bundle all components required by a Java application.
Java Database Connectivity. Allows relational databases to be accessed from a common Java interface.
Java Messaging Service
Java Naming and Directory Services
Java Transaction API
Java Transaction Services
Has a persistent superclass in the hierarchy but does not have subclasses; queries performed on the leaf class can return only instances of the leaf class.
Compare to branch class and root class.
A component of a Java class that provides a path of execution
The application registers accessor methods for the attribute.
Compare to direct access.
Ensures that each object is represented by one and only one instance in the application; that is, multiple retrievals of the same object return references to the same object instance, not multiple copies of the same object. Violating object identity can corrupt the object model.
See also identity map.
Open Database Connectivity standard; designed by Microsoft to allow relational databases from multiple vendors to be accessed via a standard interface. Supported under most operating systems including Windows NT, Windows95, OS/2, and UNIX.
Also known as write locking; allows unlimited read access to objects. A client can write an object to the database only if the object has not changed since it was last read.
Compare to pessimistic locking.
Object Transaction Service
Objects are locked before they are edited, which ensures that only one client is editing the object at any given time.
Compare to optimistic locking.
A field or combination of fields that uniquely identifies a record.
An object, which along with the home interface class, can uniquely identify an entity bean.
A relationship in which the target object is considered to be a private component of the source object; the target object cannot exist without the source and is accessible only via the source object; furthermore, if the source object is destroyed, the target object is destroyed as well.
Compare to independent relationship.
The main interface of the TopLink Mapping Workbench. The Project Tree shows the high level information stored in a project.
An object, owned by a descriptor, that controls the way the descriptor accesses the database. The query manager generates its own default SQL to access the database in a transparent manner.
TopLink supports two forms of query optimization: joining and batch reading. Their purpose is to optimize database access through reducing the number of database calls required to read a group of objects.
A group of related fields treated as a unit in a table.
In Java, a pointer to another object.
A set of tables, the contents of which can be queried through SQL.
In TopLink, a reference between two TopLink-enabled objects.
Persistent objects use relationship mappings to store references to instances of other persistent classes. The appropriate mapping class is chosen primarily by the cardinality of the relationship. TopLink provides five classes of relationship mappings.
Compare to direct mapping.
Contains columns for the primary keys of the source and target table.relational database
a database in the form of tables which have rows and columns to show the relationships between items, and in which information can be cross-referenced between two or more tables to generate a third table.
A standard Java interface that extends javax.ejb.EJBObject. The client will make method calls on the remote interface to access the bean.
Stores information about all of the instantiable classes in its subclass hierarchy. By default, queries performed on the root class return instances of the root class and its instantiable subclasses. However, the root class can be configured so that queries on it return only instances of itself without instances of its subclasses.
Compare to branch class and leaf class.
A set of unique, sequential numbers assigned to the rows of a database to provide a unique way of identifying each record
The connection between an application and the relational database that stores its persistent objects.
Provide a particular service to the client and may be stateful or stateless.
Service Provider Interface
structured query language
A foreign key where the reference is from the target object's table back to the key from the mapping's descriptor's table.
Compare to foreign key.
A TopLink Mapping Workbench tool for defining a table.
Consists of client applications, an application server that processes client requests, and a database that stores the data.
A transactional TopLink session that allows for a transaction to occur at the object level not only the database level. Changes to objects are not visible globally until the unit of work is committed.
A wrapping object used by TopLink to delay database access.
A check for the previous value of the target, accomplished through joining the source and target tables.
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