About Commands


Related Topics



Many H2OS features (and more to come) are based on commands. In some cases commands handle all of the processing for the feature, in others commands may be part of the process (such as FILTER commands).  Commands are particularly advantageous because they are modular in nature and comprise an organized collection of building blocks for future system development.


Commands are basically programs that perform specific functions and are usually named accordingly, sometimes with acronyms.   

Commands are launched (that is, executed or run) in one of these ways:



If you do not know the name of the command you wish to run, you can view (and pick up) the list of available commands by typing an =  (equals sign) on the command line and pressing ENTER. The command list will appear like this. You can now click on a row in this table to select and run a command.





For purposes of showing commands on the main screen, H2OS Commands can be added to groups, called command systems, one of which is the current commands on display, and the others available for switching to using setup->options->display controls.  


H2OS commands are an important feature because:  .



H2OS provides these types of commands:




Type of command





H2OS commands


H2OS commands are used to drive many of H2OS's features. For example, there are commands to schedule jobs, check an address, backup your database, produce a report, etc.




SQL SELECT commands


SQL Select commands are used to create temporary cursors (tables) with selected records and summaries of data in your database tables.


SQL Select is actually a mini-language in a single command. It is an extremely powerful database management tool that we, and you also, can use to achieve useful database queries. It is especially useful when joining multiple tables to obtain desired information.


SQL Select created temporary tables that are used for reviewing and printing, but  generally cannot be interacted with. That is, you can't (normally) overtype a value in an SQL created temporary table to change the underlying record.


SQL Select is best when performing sophisticated queries of your database that result in read-only displays and printed reports.


FILTER commands


Filters can be thought of as masks over your customers database that allows you to see and work with  (change/delete) selected records in the table.


Filters are best to use when performing operations that will include changes to your database.






1. FILTER commands are coded similarly to SQL SELECT commands. View and compare commands in each of these libraries for examples.