Collection Contents Index INSERT statement LEAVE statement pdf/chap9.pdf

Reference Manual
   CHAPTER 9. SQL Statements     

INSTALL statement


Function 

To make Java classes available for use within a database.

Syntax 

INSTALL JAVA
[ NEW | UPDATE ]
[ JAR jar-name ]
FROM FILE filename

Permissions 

DBA permissions are required to execute the INSTALL statement.

All installed classes can be referenced in any way by any user.

Not supported on Windows CE.

See also 

REMOVE statement

Description 

Install mode     If you specify an install mode of NEW, the referenced Java classes must be new classes, rather than updates of currently installed classes. An error occurs if a class with the same name exists in the database and the NEW install mode is used.

If you specify UPDATE, the referenced Java classes may include replacements for Java classes that are already installed in the given database.

If install-mode is omitted, the default is NEW.

JAR     If this is specified, then the filename must designate a jar file. Jar files typically have extensions of .jar or .zip.

Installed jar and zip files can be compressed or uncompressed. However, jar files produced by the Sun JDK jar utility are not supported. Files produced by other zip utilities are supported.

If the JAR option is specified, the jar is retained as a jar after the classes that it contains have been installed. That jar is the associated jar of each of those classes. The jars installed in a database with the JAR option are called the retained jars of the database.

Retained jars are referenced in INSTALL and REMOVE statements. Retained jars have no effect on other uses of Java-SQL classes. Retained jars are used by the SQL system for requests by other systems for the class associated with given data. If a requested class has an associated jar, the SQL system can supply that jar, rather than the individual class.

The jar-name is a character string value, of up to 255 bytes long. The jar-name is used to identify the retained jar in subsequent INSTALL UPDATE and REMOVE statements.

source     Specifies the location of the Java class(es) to be installed.

The formats supported for file-name include fully qualified file names, such as 'c:\libs\jarname.jar' and '/usr/u/libs/jarname.jar', and relative file names, which are relative to the current working directory of the database server.

The filename must identify either a class file, or a jar file.

Class availability 

The class definition for each class is loaded by each connection's VM the first time that class is used. When you INSTALL a class, the VM on your connection is implicitly restarted. Therefore, you have immediate access to the new class, whether the INSTALL has an install-mode of NEW or UPDATE.

For other connections, the new class is loaded the next time a VM accesses the class for the first time. If the class is already loaded by a VM, that connection does not see the new class until the VM is restarted for that connection (for example, with a STOP JAVA and START JAVA).

Standards and compatibility 

Examples 


Collection Contents Index INSERT statement LEAVE statement pdf/chap9.pdf