NonStop Server for Java (NSJ) Programmer's Guide (NSJ 2.1+)

Not supported for

current release

Referring to Database Objects

By default, the SQL/MP driver uses Guardian filenames for SQL/MP database objects, as the following table shows.

Default SQL/MP Database Object Names

Database

Object

Default Name * Examples

Catalog

[\node.][$volume.]subvol $sqldata.sales

\tokyo.$disk02.sqlcat

Index

[\node.][[$volume.]subvol.]fileID

emptab

$sqldisk.fy02.xsalary

\newyork.$sqldisk.fy02.salary

Table

* If you omit node, volume, or subvol, the SQL/MP driver uses your current node, volume, or subvolume to fully qualify

the database object name. For more information, see the SQL/MP Reference Manual.

If you are trying to obtain information about the SQL/MP system catalog and that catalog does not reside in the default

location ($system.sql), you must specify the following DEFINE before you start your Java application:

set defmode on

add_define =SQL_SYSTEMCAT_LOC class=map file=\$vol.subvol.catalogs

In your Java source code, you can always refer to SQL/MP database objects by their default Guardian file names. In some

cases, you can also refer to them by names that you choose (aliases). Aliases are useful when you port an application that can

be used on SQL databases having table names that do not conform to the table names used with SQL/MP.

The following subsections explain:

When you can use aliases●

How to create and use aliases●

Which SQL statements support aliases●

When You Can Use Aliases

You can use aliases for the following SQL/MP database objects:

Catalogs●

Collations●

Tables (including table qualifiers for columns)●

Views●

If an SQL/MP database object is not in the preceding list, you must refer to it by its default Guardian file name.

Creating and Using Aliases

To create and use aliases:

Create a java.util.Properties object.1.

Put each alias-Guardian file-name pair (called a substitution property) in the java.util.Properties object. Prefix

each alias with a plus sign (+). The individual put() calls for this step can be either in your program or in a separate

file.