Data Source Definition Commands

These are commands to define the source from which data selection will be made. How data sources are opened and closed is very much translator-specific but the commands open and close usually take one or more parameters, each being a file or directory. Typically in a network service deployment, one (or more) data sources will be opened in a startup script. They will then be available to all clients who connect to the translator service.

Data selection and fetch commands cannot be issued until a data source has been defined.

When connected to a network service, a client opening a data source in one session will have it closed automatically at the end of that session. It must be opened in the startup script to stay open between client sessions.

open

open <file> ...

Open a data source(s). Some translators will permit many data sources to be open at once, others will permit only one (e.g. a file).

This command is a no-op for database interfaces, since the database itself, specified by the -con command line option, is the data source.

close

close { all } | {<file> ... }

Close data source(s). Some translators will permit many data sources to be open at once, others will permit only one (e.g. a file). All currently open data sources may be closed at once by using close all.

This command is a no-op for database interfaces.

cd

cd <dir>

Change directory. This enables subsequent data source file names to be specified as relative path names. When this command is present in a startup script it defines the current working directory for all client sessions. Any cd command used within a client session is valid only until the end of the session. The directory name <dir> may contain environment variables.

Running example

Startup Script:

# Define the base directory as the arcinfo tree
cd g:/arcinfo
 
# Open a coverage
open brisbane