JDBC-ODBC Bridge Enhancements - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

JDBCTM-ODBC Bridge Enhancements

JDK 1.2 Contents JDBC

The JDBC-ODBC Bridge allows Java programs to use JDBC with many existing ODBC drivers. The Bridge is itself a JDBC driver defined in the class sun.jdbc.odbc.JdbcOdbcDriver. The Bridge defines the JDBC subprotocol odbc.

Status of the JDBC-ODBC Bridge

The JDBC-ODBC Bridge should be considered a transitional solution. Javasoft and Intersolv are working to make the Bridge more reliable and robust, but they do not consider it a supported product. In the near future, development of pure-Java JDBC Drivers will make the JDBC-ODBC Bridge unnecessary.

Why not just use ODBC?

The JDBC-ODBC Bridge offers several advantages over "naked" ODBC.

• The ODBC API is strongly oriented toward C/C++ programmers. The JDBC-ODBC Bridge makes it unnecessary for the Java programmer to deal with non-Java concepts.

• The ODBC API is extremely complex and intermingles high-level and low-level functions. The JDBC-ODBC Bridge allows the programmer to rely on the JDBC API, which is relatively simple and easy to learn.

• The JDBC-ODBC Bridge lets a program deal with ODBC through a standardized JDBC interface. That helps a program avoid being tied to ODBC when a better solution comes along.

Why use ODBC at all?

The Java programmer's ideal is "Pure Java": no native code, no platform-dependent features. But you may need to begin your development effort right away, without waiting for your DBMS to offer a Java-only JDBC Driver. Partly-native Drivers, such as the JDBC-ODBC Bridge, let you create programs that easily adapt to Pure Java drivers as they become available.

What's new with the JDBC-ODBC Bridge?

• The Bridge has been re-implemented using the Java Native Interface API, for improved performance and stability.

• A jdbc:odbc: connection can now have a charSet property, to specify a Character Encoding Scheme other than the client default. For possible values, see the JDK 1.1 Internationalizaton specification on the Javasoft Web Site.

• The Bridge now assumes that ODBC drivers are able to handle multi-threaded access. This will improve performance. If you need to use multi-threading and your ODBC package does not support it, your client program will have to implement locking.