Difference between revisions of "Query"

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(Navigation Introduction)
(Navigating Display)
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==== Navigating Display ====
 
==== Navigating Display ====
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Assuming the query definition is going to a screen, as opposed to a report or work file, there are two places on top where you can key something, and a few commands available.
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Upper Left corner is used for specifying some line number you want to jump to, or "B" for Bottom, or "T" for Top again.  You can also scroll through the data.
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Upper Right corner is used for specifying some sideways byte count you want to leap to.  You can also use F20 (upper shift F8) to go to the right, or F19 (upper shift F7) to go to the left.
  
 
== Query vs. High Level Languages ==
 
== Query vs. High Level Languages ==

Revision as of 12:49, 11 June 2005

Query/400 is a basic user oriented database report writer.

It is designed to allow non-technical users to create basic reports and online inquiries in a simple, menu driven way.

It is a tool that is pretty safe to put into the hands of users, so long as we know how to prevent them from creating an *OUTFILE that gets same name as a pre-existing real file in our data base.

See CLP/400 examples of CLP programs that give people access to Query stuff that can go on a Menu, so that they do not have Command Line Access which has some security concerns.

Query Tips and Techniques

Here are links to "how to" do various things in Query, in which Query is part of the name of the topic, so that other people can use the same name with SQL or RPG or some other 400 tool to get similar results.

Navigation Introduction

If you are new to Query, some access options may be non-obvious at first. This info is also for end users of Query Definitions, who may be infrequent users of Query, accessing it from a Menu, not neccessarily knowing what is a HLL, Query, something else.

Selection Criteria

After launching a previously defined query definition, or a file dump, you get to a familiar selection screen with top 1/2 being space to specify what to include, and bottom half being a director of field names.

If the bottom 1/2 does not give textual explanations for the fields, use F11 to toggle between how they are listed. Move cursor to bottom 1/2 then scroll to see what field names can be entered in the top 1/2 as part of selection criteria.

Navigating Display

Assuming the query definition is going to a screen, as opposed to a report or work file, there are two places on top where you can key something, and a few commands available.

Upper Left corner is used for specifying some line number you want to jump to, or "B" for Bottom, or "T" for Top again. You can also scroll through the data.

Upper Right corner is used for specifying some sideways byte count you want to leap to. You can also use F20 (upper shift F8) to go to the right, or F19 (upper shift F7) to go to the left.

Query vs. High Level Languages

Query Advantages vs. HLL

On short notice, we generally can get a new query/400 written and into operation faster than a new program, if all we have are native 400 editors. Non-programmers can rapidly get at simple lists and inquiries.

From Command Line

  • RUNQRY *N then name of some file
    • this gets us a fast dump of the file contents, without needing a query definition
    • use F4 instead of enter ... and we get at selection criteria and other options

HLL Advantages vs. Query

In terms of general 400 perromance, Query cannot hold a candle to High Level Languages like ROG and SQL. Query/400 is a resource hog.

Query is somewhat limited on numbers of files to join and inter-link.