Commands are basically programs that perform specific functions and
are usually named accordingly.
Commands are launched (that is, executed or run) in one of these ways:
clicking the command's button (if the command
button is in the current command system)
typing the command's name in the command entry
field on the main screen prefixed with an = sign. For example =JOB runs
the JOB command to schedule a job for the currently selected customer,
and there is also a JOB command button that can be added to your command
system.
selecting the command from the command
history
if the command has been previously issued
menu selection (for commands that appear in your
menu system)
Commands buttons are arranged in groups called command systems, any one of which is designated the current command system and is displayed on your screen.
The H2OS command system is an important feature of H2OS's modular design because: .
it allows us to extend H2OS by 'plugging in' new
and revised commands seamlessly.
It comprises an Application Program Interface
(API) that can be used by 3rd party programmers to add
specialized commands that can read (but not change) data stored in
your H2OS database.
We can choose which commands we wish to see on
our screens from the many commands available.
H2OS provides these types of commands:
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Type of command |
Explanation
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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.
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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. |
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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.
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1. FILTER commands are coded similarly to SQL SELECT commands. View and compare commands in each of these libraries for examples.