qr barcode generator vb.net EJB 2.0 Enhancements in Software

Print QR Code ISO/IEC18004 in Software EJB 2.0 Enhancements

EJB 2.0 Enhancements
QR Code ISO/IEC18004 Reader In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Quick Response Code Encoder In None
Using Barcode maker for Software Control to generate, create QR Code image in Software applications.
EJB 2.0, published in April 2001, represented a major revision to the EJB specification. Many of the enhancements in EJB 2.0 were incompatible with the corresponding capabilities in EJB 1.x. To avoid breaking EJB 1.x-compatible beans, EJB 2.0 provides complementary capabilities in these areas, allowing side-by-side coexistence of EJB 1.x and EJB 2.0 beans. A complete description of the differences between EJB 1.x and EJB 2.0 is well beyond the scope of this book. However, several of the differences were motivated by difficulties in using container-managed persistence under the EJB 1.x specification, and those changes directly affect database processing within EJBs.
Recognizing QR Code In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
QR Code 2d Barcode Generation In Visual C#
Using Barcode encoder for .NET framework Control to generate, create QR image in .NET applications.
22:
Paint QR Code JIS X 0510 In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create QR-Code image in ASP.NET applications.
QR Code JIS X 0510 Drawer In VS .NET
Using Barcode encoder for VS .NET Control to generate, create QR image in .NET applications.
SQL and Application Servers
QR Code Maker In VB.NET
Using Barcode creator for .NET Control to generate, create QR Code 2d barcode image in VS .NET applications.
Encoding Barcode In None
Using Barcode creator for Software Control to generate, create barcode image in Software applications.
One difficulty with EJB 1.x has already been mentioned the difficulty of modeling complex objects that draw their data from multiple database tables or that contain nonrelational structures like arrays and hierarchical data. With EJB 1.x, you could model a complex object as a family of inter-related entity beans, each drawn from one table. This approach allowed the use of container-managed persistence, but the relationships between pieces of the object need to be implemented in applications code within the bean. Ideally, these internal details within the complex object should be hidden from applications code. Alternatively, with EJB 1.x, you could model a complex object as a single entity bean, with data in the bean s instance variables drawn from multiple related tables. This achieves the desired application code transparency, but container-managed persistence could be used when an entity bean draws its data from multiple tables. EJB 2.0 addressed this issue through the use of abstract accessor methods, which are used to set and retrieve every persistent instance variable within an entity bean. The container actually maintains the storage for the variables and the variable values. The bean explicitly calls a get() accessor method to retrieve an instance variable value and a set() accessor method to set its value. Similarly, there are get() and set() abstract accessor methods for every relationship that links the rows in the database that contribute data to the entity bean. Many-to-many relationships are easily handled by mapping them into Java collection variables. With these new features, the container has complete knowledge of all the instance variables used by a bean, and of every access that code within the bean makes to the instance variables. The entity bean can represent a complex object that draws data from multiple database tables, hiding the details from the applications code. But containermanaged persistence can now be used, because the container knows all about the various parts of the object and the relationships among the parts. Another problem with the EJB 1.x specification is that while database interactions were standardized, the finder methods that are used to search the active entity beans were not. The finder methods implement capabilities like searching for a particular entity bean by primary key, or searching for the set of beans that match a particular criterion. Without this standardization, portability across application servers was compromised, and searches of entity beans often required recourse to searching the underlying database. EJB 2.0 addressed the searching limitations through the use of abstract select methods that search entity beans. The select methods use a newly defined EJB 2.0 Query Language (EJBQL). While the query language is based on SQL, it includes constructs such as path expressions that are decidedly nonrelational. Finally, EJB 2.0 was designed to align with the SQL standard and its abstract data types. Support for these types somewhat simplifies the interaction between entity beans and the database for DBMS products that support abstract types. At this time, few DBMS products support them.
Barcode Creator In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
ANSI/AIM Code 39 Generator In None
Using Barcode maker for Software Control to generate, create USS Code 39 image in Software applications.
EJB 3.0 Enhancements
Code 128 Code Set C Maker In None
Using Barcode encoder for Software Control to generate, create Code 128 Code Set C image in Software applications.
GS1 - 13 Drawer In None
Using Barcode generator for Software Control to generate, create EAN13 image in Software applications.
The EJB 3.0 specification, published in draft form in 2004 and in final form in 2006, makes the container do more work, thus making programming less work and much simpler. It decreases the amount of program code that developers must provide, including eliminating the requirement for ejb(method) callback methods, and reduces the complexity of entity bean programming.
Printing British Royal Mail 4-State Customer Barcode In None
Using Barcode creator for Software Control to generate, create RM4SCC image in Software applications.
Bar Code Reader In .NET
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
Painting European Article Number 13 In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create GS1 - 13 image in Eclipse BIRT applications.
Code39 Creation In Java
Using Barcode creator for Java Control to generate, create Code 3/9 image in Java applications.
Bar Code Creation In .NET
Using Barcode creation for Reporting Service Control to generate, create barcode image in Reporting Service applications.
2D Barcode Maker In Visual Studio .NET
Using Barcode creator for ASP.NET Control to generate, create 2D Barcode image in ASP.NET applications.
Making EAN / UCC - 13 In C#.NET
Using Barcode printer for VS .NET Control to generate, create GS1 - 13 image in .NET applications.
Code39 Generator In VB.NET
Using Barcode maker for VS .NET Control to generate, create Code 3 of 9 image in .NET framework applications.
Copyright © OnBarcode.com . All rights reserved.