In the two-level model, a Java application talks specifically to the information source. This requires a JDBC driver that can speak with the specific information source being gotten to. A client's directions are conveyed to the database or other information source, and the aftereffects of those announcements are sent back to the client. The information source might be situated on another machine to which the client is associated by means of a system. This is alluded to as a customer/server design, with the client's machine as the customer, and the machine lodging the information source as the server. The system can be an intranet, which, for instance, associates representatives inside a company, or it very well may be the Internet.
In the three-level model, directions are sent to a "center level" of administrations, which at that point sends the directions to the information source. The information source forms the directions and sends the outcomes back to the center level, which at that point sends them to the client. MIS chiefs locate the three-level model exceptionally alluring in light of the fact that the center level makes it conceivable to keep up power over access and the sorts of updates that can be made to corporate information. Another favorable position is that it streamlines the sending of utilizations. At last, as a rule, the three-level engineering can give execution points of interest.
The DBMS-restrictive convention gives two-path correspondence between the database server and the server machine. HTTP, RMI, CORBA or different calls give two path correspondence between the server machine and the customer machine
As of not long ago, the center level has frequently been written in dialects, for example, C or C++, which offer quick execution. In any case, with the presentation of enhancing compilers that make an interpretation of Java bytecode into effective machine-explicit code and innovations, for example, Enterprise JavaBeans™, the Java stage is quick turning into the standard stage for center level advancement. This is a major furthermore, making it conceivable to exploit Java's power, multithreading, and security highlights.
With ventures progressively utilizing the Java programming language for composing server code, the JDBC API is being utilized increasingly more in the center level of a three-level engineering. A portion of the highlights that make JDBC a server innovation are its help for association pooling, conveyed exchanges, and detached rowsets. The JDBC API is additionally what enables access to an information source from a Java center level.