Using Java Classes in SQL

This chapter describes how to use Java classes in an Adaptive Server environment. The first sections give you enough information to get started; succeeding sections provide more advanced information.

In this document, SQL columns and variables whose datatypes are Java-SQL classes are described as Java-SQL columns and Java-SQL variables or as Java-SQL data items.

The sample classes used in this chapter can be found in:

$SYBASE/$SYBASE_ASE/sample/JavaSql (UNIX)
%SYBASE%\Ase-12_5\sample\JavaSql (Windows NT)

General concepts

Java considerations

Java-SQL names

Using Java classes as datatypes

Creating and altering tables with Java-SQL columns

Selecting, inserting, updating, and deleting Java objects

Invoking Java methods in SQL

Sample methods

Exceptions in Java-SQL methods

Representing Java instances

Assignment properties of Java-SQL data items

Datatype mapping between Java and SQL fields

Character sets for data and identifiers

Subtypes in Java-SQL data

Widening conversions

Narrowing conversions

Runtime versus compile-time datatypes

The treatment of nulls in Java-SQL data

References to fields and methods of null instances

Null values as arguments to Java-SQL methods

Null values when using the SQL convert function

Java-SQL string data

Zero-length strings

Type and void methods

Java void instance methods

Java void static methods

Equality and ordering operations

Evaluation order and Java method calls

Columns

Variables and parameters

Static variables in Java-SQL classes

Java classes in multiple databases

Scope

Cross-database references

Inter-class transfers

Passing inter-class arguments

Temporary and work databases

Java classes


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