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 "Sample Java Classes " and in $SYBASE/$SYBASE_ASE/sample/JavaSql (UNIX) or %SYBASE%\Ase-12_0\sample\JavaSql (Windows NT).

General Considerations

Java-SQL Names

Using Java Classes as Datatypes

Creating Tables with Java-SQL Columns

Selecting, Inserting, Updating, and Deleting Java Objects

Referencing Java Fields in SQL

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 vs. 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

Call-by-Reference for Java Methods

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

Sample Java Classes


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