Reference Manual
   CHAPTER 7. SQL Data Types     

Java class data types

Function 

Any Java class that is installed into a database can be used as a SQL data type. Java class data types provide abstract data types for use within the database.

Built-in and user-defined Java classes 

Java classes in the database fall into one of the following categories:

• Built-in classes     A subset of the Java API is installed into all Java-enabled databases.

• User-defined classes     Users with DBA permission can install compiled Java classes into a database.

  Case sensitivity of Java class data types

Java identifiers, including data types, are case sensitive: the Java int data type cannot be written as INT. SQL identifiers, including data types, are case insensitive. The int data type can also be written as Int or any other combination of upper and lower case characters.

When a Java class is used as a SQL data type, the data type is always case sensitive. This is an exception to the rule for SQL identifier case insensitivity.

Example 

If you install a class named Demo, the following statements are not equivalent:

CREATE TABLE t1 (
   id INT PRIMARY KEY
   demo_column Demo )
CREATE TABLE t1 (
   id INT PRIMARY KEY
   demo_column DEMO )

  Built-in Java classes

This section lists the built-in classes available for use as SQL data types in a Java-enabled database.

  java.beans classes

The following table lists the supported classes, interfaces, and exceptions from java.beans.

Class	Interface	Exception
BeanDescriptor	BeanInfo	IntrospectionException
Beans	Customizer	PropertyVetoException
EventSetDescriptor	PropertyChangeListener
FeatureDescriptor	PropertyEditor
IndexedPropertyDescriptor	VetoableChangeListener
Introspector	Visibility
MethodDescriptor
ParameterDescriptor
PropertyChangeEvent
PropertyChangeSupport
PropertyDescriptor
PropertyEditorManager
PropertyEditorSupport
SimpleBeanInfo
VetoableChangeSupport

  java.lang classes

The following table lists the supported classes, interfaces, and exceptions from java.lang.

Class	Interface	Exception
Boolean	Cloneable	ArithmeticException
Byte	Runnable	ArrayIndexOutOfBoundsException
Character		ArrayStoreException
Class		ClassCastException
ClassLoader		ClassNotFoundException
Compiler		CloneNotSupportedException
Double		Exception
Float		IllegalAccessException
Integer		IllegalArgumentException
Long		IllegalMonitorStateException
Math		IllegalStateException
Number		IllegalThreadStateException
Object		IndexOutOfBoundsException
Process		InstantiationException
Runtime		InterruptedException
( not supported: SecurityManager )		NegativeArraySizeException
Short		NoSuchFieldException
String		NoSuchMethodException
StringBuffer		NullPointerException
System (not supported: Thread, ThreadGroup)		NumberFormatException
Throwable		RuntimeException
Void		SecurityException
		StringIndexOutOfBoundsException

  java.lang.reflect classes

The following table lists the supported classes, interfaces, and exceptions from java.lang.reflect.

Class	Interface	Exception
Array	Member	InvocationTargetException
Constructor
Field
Method
Modifier

  java.math classes

The following table lists the supported classes from java.math.

Class	Interface	Exception
BigDecimal
BigInteger

  java.sql classes

The following table lists the supported classes, interfaces, and exceptions from java.sql.

Class	Interface	Exception
Date	CallableStatement	DataTruncation
DriverManager	Connection	SQLException
DriverPropertyInfo	DatabaseMetaData	SQLWarning
Time	Driver
Timestamp	PreparedStatement
Types	ResultSet
	ResultSetMetaData
	Statement

  java.text classes

The following table lists the supported classes, interfaces, and exceptions from java.text.

Class	Interface	Exception
BreakIterator	CharacterIterator	ParseException
ChoiceFormat
CollationElementIterator
CollationKey
Collator
DateFormat
DateFormatSymbols
DecimalFormat
DecimalFormatSymbols
FieldPosition
Format
MessageFormat
NumberFormat
ParsePosition
RuleBasedCollator
SimpleDateFormat
StringCharacterIterator

  java.util classes

The following table lists the supported classes, interfaces, and exceptions from java.util.

Class	Interface	Exception
BitSet	Enumeration	EmptyStackException
Calendar	EventListener	MissingResourceException
Date	Observer	NoSuchElementException
Dictionary		TooManyListenersException
EventObject
GregorianCalendar
Hashtable
ListResourceBundle
Locale
Observable
Properties
PropertyResourceBundle
Random
ResourceBundle
SimpleTimeZone
Stack
StringTokenizer
TimeZone
Vector

  java.util.zip classes (Compression utilities)

The following table lists the supported classes, interfaces, and exceptions from java.util.

Class	Interface	Exception
Adler32	Checksum	DataFormatException
CRC32		ZipException
CheckedInputStream
CheckedOutputStream
Deflater
DeflaterOutputStream
GZIPInputStream
GZIPOutputStream
Inflater
InflaterInputStream
ZipEntry
ZipFile
ZipInputStream
ZipOutputStream

  java.io classes

The following table lists the supported classes, interfaces, and exceptions from java.io.

Class	Interface	Exception
BufferedInputStream	DataInput	CharConversionException
BufferedOutputStream	DataOutput	EOFException
BufferedReader	Externalizable	FileNotFoundException
BufferedWriter	FilenameFilter	IOException
ByteArrayInputStream	ObjectInput	InterruptedIOException
ByteArrayOutputStream	ObjectInputValidation	InvalidClassException
CharArrayReader	ObjectOutput	InvalidObjectException
CharArrayWriter	Serializable	NotActiveException
DataInputStream		NotSerializableException
DataOutputStream		ObjectStreamException
File		OptionalDataException
FileDescriptor		StreamCorruptedException
FileInputStream		SyncFailedException
FileOutputStream		UTFDataFormatException
FileReader		UnsupportedEncodingException
FileWriter		WriteAbortedException
FilterInputStream
FilterOutputStream
FilterReader
FilterWriter
InputStream
InputStreamReader
LineNumberInputStream
LineNumberReader
ObjectInputStream
ObjectOutputStream
ObjectStreamClass
OutputStream
OutputStreamWriter
PipedInputStream
PipedOutputStream
PipedReader
PipedWriter
PrintStream
PrintWriter
PushbackInputStream
PushbackReader
RandomAccessFile
Reader
SequenceInputStream
StreamTokenizer
StringBufferInputStream
StringReader
StringWriter
Writer

  Unsupported packages and classes

The following packages are not supported in the Sybase VM:

• java.applet

• java.awt

• sun.applet

• sun.audio

• sun.awt

• sun.beans.editors

• sun.beans.infos

• sun.jdbc.odbc

• sun.misc

• sun.net

• sun.rmi

• sun.security

• sun.tools

• sunw.io

• sunw.util

The following classes are only partially supported. They may have some unsupported native methods

• java.lang.ClassLoader

• java.lang.Compiler

• java.lang.Runtime (exec/load/loadlibrary)

• java.lang.SecurityManager

• java.lang.Thread

• java.io.File

• java.io.FileDescriptor

• java.io.FileInputStream

• java.io.FileOutputStream

• java.io.ObjectInputStream

• java.io.ObjectOutputStream

• java.io.ObjectStreamClass

• java.io.PrintStream

• java.io.RandomAccessFile

• java.math.BigInteger

• java.net.PlainDatagramSocketImpl

• java.util.zip.Adler32

• java.util.zip.CRC32

• java.util.zip.Deflater

• java.util.zip.Inflater

  User-defined Java classes

Users with DBA permissions can install Java classes into a database. Any class installed into the database becomes available as a data type.

Preparing classes using the JDK 

The Java Development Kit (JDK) provides the tools necessary for preparing classes for installation into a database.

  To prepare a class for installation, using the JDK:

1. Using a text editor, write a Java class, outside the database, and store it as a Java source code file (typically with an extension of .java).

   For example, you may create a file named MyFirstClass.java.

2. Using the javac compiler, compile the Java class to produce a Java class file (with .class extension).

   For example, to compile the file MyFirstClass.java, type the following at a command prompt:

   javac MyFirstClass.java

Installing a class 

Once you have a compiled Java class file, you can install it into the database. You can do this conveniently using either Sybase Central or Interactive SQL.

  To install a class, using Sybase Central:

1. From Sybase Central, connect to the database as a user ID with DBA permissions.

2. Open the Java Objects folder, and double-click Add Java Class or Jar. Follow the instructions in the wizard to install the class.

  To install a class, using Interactive SQL:

1. From Interactive SQL, connect to the database as a user ID with DBA permissions.

2. Enter the following command to install the class:

   INSTALL JAVA NEW FROM filename

  Using classes as data types

Creating tables using Java class data types 

You can create a table with columns based on a Java class data type, just as you can with any other data type. For example, if MyClass is a Java class installed into the database, you can create a table using this class as follows:

CREATE TABLE mytable (
   id INT NOT NULL PRIMARY KEY,
   mycol MyClass )

In this statement, the MyClass data type is a SQL data type, and so is case-insensitive, even though Java is a case-sensitive language.

Inserting Java objects 

You can insert a Java object into a table just as you would any other row, using the INSERT statement. Because each row is a separate instance of the class, you must use the NEW keyword to create an instance. For example,

INSERT INTO t2
VALUES ( 1, NEW MyClass() )

In this case, MyClass() is a Java class name, not a SQL data type, and so must be entered in the proper case.

In this example, MyClass() has no arguments, so each row is created using the default constructor. In general, you would supply arguments to a class to place distinct values in each row.

Using subclasses 

If you install a class, say MySubClass, which is a subclass of MyClass, you can insert instances of MySubClass into a column of data type MyClass.