Accessing Databases Using JDBC - Java Programming: Comprehensive Concepts and Techniques - page 708

10. Click the OK button in the ODBC Data Source Administrator dialog box.
Click the Close button on the Administrative Tools window title bar.
The ODBC data source name is registered and the ODBC data source is
available for use.

Once an ODBC data source exists, a connection to the database may be
established. This connection is made within a Java program by using JDBC™.

Connecting to a Database Using JDBC™

A major benefit of using JDBC™ is interoperability , which means the
underlying database used in an application can change with essentially no
change to the application. Using the JDBC™ API to access a database keeps the
application isolated from the peculiarities of a specific DBMS, as long as an
appropriate driver is used. A JDBC™ driver is software for a specific DBMS and
effectively translates between the functionality of the JDBC™ API and the
corresponding commands of the DBMS. The application program uses the
JDBC™ API, keeping the Java code consistent regardless of the DBMS used;
JDBC™, in turn, communicates to the DBMS through the specific JDBC™
driver. Table 11-4 lists the four types of JDBC™ drivers.

Table 11-4 JDBC™ Driver Types

TYPE NAME DESCRIPTION PROS CONS

Type 1 JDBC-ODBC Calls go through Bridge, Access to many databases Performance degraded;

Bridge then to driver, then to through ODBC drivers ODBC, ODBC driver

native database interface needed for specific

database on local (client)
machine

Type 2 Native-API/ Variation on JDBC-ODBC Better performance than Requires binary code

partly Java bridge, but converts JDBC Bridge (vendor database library)

calls into database-specific on client machine; lower

calls and so communicates performance than Types

directly with database 3 and 4

server

Type 3 net-protocol/ Three-tiered; translates calls Can handle multiple Java Requires database-specific

all-Java into DBMS-independent clients connecting to coding in middle tier;

net protocol, then multiple databases; sup- traversing query result

translated to DBMS ports advanced features, sets may take longer

protocol by middleware such as logging, auditing, due to path through

server caching, and load- backend server

balancing; in general,
the most flexible solution

Type 4 Native Similar to Type 2 but Performance; no special Needs different driver for

protocol/ 100% Java; converts JDBC client or server software each database

all Java calls into native calls for needed; drivers can be

database downloaded dynamically