Data Access Using JDBC

Java applications that hold some or all classes in the database have significant advantages over traditional SQL stored procedures. At an introductory level, however, it may be helpful to use the parallels with SQL stored procedures to demonstrate the capabilities of JDBC. In the following examples, you write Java classes that insert a row into the Departments table.

As with other interfaces, SQL statements in JDBC can be either static or dynamic. Static SQL statements are constructed in the Java application and sent to the database. The database server parses the statement, selects an execution plan, and executes the statement. Together, parsing and selecting an execution plan are referred to as preparing the statement.

If a similar statement has to be executed many times (many inserts into one table, for example), there can be significant overhead in static SQL because the preparation step has to be executed each time.

In contrast, a dynamic SQL statement contains place holders. The statement, prepared once using these place holders, can be executed many times without the additional expense of preparing.

• Preparing for the JDBC Examples
  The code fragments in the following sections are taken from the complete class in %ALLUSERSPROFILE%\SybaseIQ\samples\SQLAnywhere\JDBC\JDBCExample.java. In preparation for these sections, the sample Java application is compiled and installed into the database.
• Inserts, Updates, and Deletes Using JDBC
  Static SQL statements such as INSERT, UPDATE, and DELETE, which do not return result sets, are executed using the executeUpdate method of the Statement class. Statements, such as CREATE TABLE and other data definition statements, can also be executed using executeUpdate.
• Using Static INSERT and DELETE Statements from JDBC
  A sample JDBC application is called from the database server to insert and delete rows in the Departments table using static SQL statements.
• How to Use Prepared Statements for More Efficient Access
  If you use the Statement interface, you parse each statement that you send to the database, generate an access plan, and execute the statement. The steps before execution are called preparing the statement.
• Using Prepared INSERT and DELETE Statements from JDBC
  A sample JDBC application is called from the database server to insert and delete rows in the Departments table using prepared statements.
• JDBC Batch Methods
  The addBatch method of the PreparedStatement class is used for performing batched (or wide) inserts. The following are some guidelines to using this method.
• How to Return Result Sets from Java
  This section describes how to make one or more result sets available from Java methods.
• Returning Result Sets from JDBC
  A sample JDBC application is called from the database server to return multiple result sets.
• JDBC Notes
  Learn about privileges for accessing and executing Java classes.