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OS/2 Help File
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1994-07-12
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ΓòÉΓòÉΓòÉ 1. Welcome ΓòÉΓòÉΓòÉ
ΓòÉΓòÉΓòÉ <hidden> Dummy ΓòÉΓòÉΓòÉ
ΓòÉΓòÉΓòÉ <hidden> Dummy ΓòÉΓòÉΓòÉ
Welcome to the
Visualizer
SQL View Tutorial
(C) Copyright IBM Corporation 1994
Double-click on the arrow to continue.
ΓòÉΓòÉΓòÉ 2. Using this Tutorial ΓòÉΓòÉΓòÉ
Using this tutorial
The Visualizer tutorial windows have been designed to occupy only 40 percent of
your screen. This is to allow you to run Visualizer at the same time as viewing
a tutorial.
In this way you can perform the tutorial steps using the real product and not a
product simulation as in so many online tutorials.
Before you start to read the lesson steps, it is recommended that you will:
o Open the Visualizer folder
o Size the Visualizer window so that it fits neatly next to the tutorial window
By performing the tutorial steps using the real Visualizer product, you will
familiarize yourself with the feel, functions, and features of the product.
All the tutorials in the Visualizer product are structured in a similar way. If
you have not used a Visualizer tutorial before, double-click on any of the
following topics for further information:
o Highlighted terms
o Lessons and steps
o Why
o Which lessons to follow
ΓòÉΓòÉΓòÉ <hidden> Lessons and Steps ΓòÉΓòÉΓòÉ
Lessons and steps
Visualizer tutorials are divided into lessons and each lesson is further
divided into steps.
At the start of each lesson there is a lesson overview, followed by a list of
lesson steps. The lesson steps are hypertext links to the steps themselves. To
start the tutorial at the beginning, double-click on the first step.
At the end of each lesson there is an overview which recaps on the concepts and
steps you should be familiar with.
ΓòÉΓòÉΓòÉ <hidden> Highlighted Terms ΓòÉΓòÉΓòÉ
Highlighted terms
If you see any words or phrases that are highlighted like this: hypertext you
can double-click on them to get more information.
The information is displayed in a new window like this one. When you have
finished reading it, close the window in one of the following ways:
o Press the Esc key on your keyboard
o Double-click on the System menu
o Select Close from the System menu
ΓòÉΓòÉΓòÉ <hidden> Why ΓòÉΓòÉΓòÉ
Why
At the start of each lesson you will see this:
(Why?)
Double-clicking on the word (Why?) will display further information about the
purpose of the lesson and help to explain how the lesson is related to the
lessons which precede and follow it.
ΓòÉΓòÉΓòÉ <hidden> Which Lessons to Follow ΓòÉΓòÉΓòÉ
Which lessons to follow
If you are unfamiliar with Visualizer, we recommend that you work through each
lesson sequentially.
To do this, when you have read the overview of each lesson, double-click on the
title of the first lesson.
If you are familiar with some aspects of Visualizer, be selective about which
lessons you work through. Read all the lesson overviews before you select which
lessons you want to follow.
To go on to other lessons, follow the navigational help that is given at the
end of each lesson.
ΓòÉΓòÉΓòÉ 3. Visualizer SQL View Lessons ΓòÉΓòÉΓòÉ
Visualizer SQL View Lessons
Use a Visualizer SQL view object to look at a subset of information from
selected SQL tables. The information in an SQL view can be taken from just one
table in a database, or from several tables.
If an SQL view object is read-only you can use it to browse the information in
a database.
If an SQL view object can be updated, you can use it to change or add
information to a database as well as browse information.
An SQL view can be included in an SQL database object, its contents can be
printed, and it can be used as the data source for a report or a query.
Lesson 1: Looking at data in an SQL view
In this lesson you will learn how to use an existing SQL view object to look at
data.
This lesson takes 10 minutes to complete.
Lesson 2: Creating a new SQL view based on an existing one
In this lesson you will create a new SQL view object based on an existing SQL
view. You will also read about how to create your own SQL View template.
This lesson takes 25 minutes to complete.
ΓòÉΓòÉΓòÉ 4. 1. Looking at Data in a View ΓòÉΓòÉΓòÉ
Looking at Data in a View
When you catalog an existing database the views in that database are available
for you to work with. You might need to update information in a view, add
information to a view, or remove information from a view.
In this lesson you will learn how to use an existing SQL view to look at a
subset of data in a database.
(Why?...)
Steps
1. Open an existing SQL view.
2. Look at the data.
3. Save any changes then close the view.
ΓòÉΓòÉΓòÉ 4.1. 1.1 Open an SQL View ΓòÉΓòÉΓòÉ
When Visualizer was first installed on your computer, SQL database objects were
created for all the databases you have access to. These objects contain icons
for the SQL tables and SQL views that are available for use with each database.
For more information about SQL database objects read the SQL Database tutorial.
Open an SQL database object that you have access to.
The SQL database object contains icons that represent the tables and views
associated with this database.
Open an SQL view by double-clicking on its icon.
The SQL view opens. It displays rows and columns of information, and is similar
in layout to an SQL table or Visualizer table.
Information at the bottom of the view shows the number of rows of data
retrieved from the database (the Number of rows fetched) and the maximum number
of rows that can be retrieved from the database (the Fetch limit).
If the view is in browse mode you cannot change or add information.
If the view is in update mode you can make changes or add information.
ΓòÉΓòÉΓòÉ 4.2. 1.2 Look at the data ΓòÉΓòÉΓòÉ
You can always look at the contents of an SQL view, whether it is in browse or
update mode. However, you can only change or add data to an SQL view if the
view is is in update mode.
Sroll through the view, looking at the data.
If allowed, make any changes you want to.
Making changes and adding data to an SQL view is very similar to making changes
and adding data to an SQL table or Visualizer table.
For more information on changing data, read the SQL Table and the Visualizer
Table tutorials.
ΓòÉΓòÉΓòÉ 4.3. 1.3 Save and Close ΓòÉΓòÉΓòÉ
Select from the tool bar, if you have made changes to your SQL vIew,
The changes you have just made to your SQL view have been saved.
If you make changes to any Visualizer object and try to close the object
without saving the changes, Visualizer will ask you to confirm that you really
do want to close the object without saving the changes. In this way you should
never lose work that you have forgotten to save.
Double-click on the title-bar icon.
Your SQL view is now closed.
ΓòÉΓòÉΓòÉ <hidden> Why Look at a View? ΓòÉΓòÉΓòÉ
SQL databases can hold enormous amounts of information. Usually more
information than you would ever need! This is when SQL views become especially
useful.
You can use an SQL view to look at a subset of the information in a database,
without having to looking at all the other information that the database
contains.
An SQL view stores details of precisely which information you need to look at.
In this way you can quickly and easily access precisely the information you
need. However, to do this you must know how to open an SQL view and how to look
at the information it contains. Read through this short lesson and you will
learn how to do this.
ΓòÉΓòÉΓòÉ 5. 2. Creating a new SQL View ΓòÉΓòÉΓòÉ
Creating a new SQL view
You can create a new SQL view in one of three different ways:
o You can base your new SQL view on an existing SQL view
o You can use an SQL View template that you have created
o You can use the SQL View template provided with Visualizer
In this lesson you will create a new SQL view based on an existing SQL view.
You will also read about how to create your own SQL View template.
(Why?...)
Steps
1. Create your new SQL view from an existing one.
2. Change the settings for the new view.
3.Apply the view then close it.
ΓòÉΓòÉΓòÉ 5.1. 2.1 Create a new SQL View ΓòÉΓòÉΓòÉ
Locate the existing SQL view that you want to base your new view on.
You can use an existing SQL view from any folder.
Select the existing SQL view object.
The menu for the existing SQL view object is displayed.
Select Create from from the menu.
An icon for your new SQL view object is created and displayed in the same
folder as the existing one.
If you want to move your new SQL view to a different folder, simply drag it and
drop it onto the new folder,
ΓòÉΓòÉΓòÉ 5.2. 2.2 Change the Settings ΓòÉΓòÉΓòÉ
To change any of the settings for your new SQL view object, and to apply the
view to a database, you use the new object's Settings notebook.
Display the menu for your new SQL view by selecting the SQL View icon.
Select on the arrow to the right of Open.
Select the Settings choice.
The Settings notebook for your new SQL view object is now open and displayed on
your screen
If you want to make the view different to the original one that it was based
on, modify the information for the view or its columns.
If you want to create an SQL View template which you could use to create
several similar SQL views, check the Template check box on the General page of
the Settings notebook. If you do create a template view, remember not to apply
the template view to a database. (Applying a view to a database is discussed in
the next step.)
Do not close the Settings notebook just yet as you still have to apply the view
to the database.
ΓòÉΓòÉΓòÉ 5.3. 2.3 Apply the View then Close it ΓòÉΓòÉΓòÉ
Before you can use your new SQL view to look at a database you must apply its
settings to the database.
Select the View tab on the Settings notebook.
The View page on the Settings notebook is opened.
Select Apply all on the View page of the Settings notebook.
Close the Settings notebook by double-clicking on the System menu in the top
left corner of the notebook.
The changes you have made to your new SQL view object are saved, the view is
applied to the database, and the Settings notebook closes.
Your new SQL view is now ready for you to use.
ΓòÉΓòÉΓòÉ <hidden> Why Create a new SQL View ΓòÉΓòÉΓòÉ
An SQL view stores details of precisely which information you need to look at.
In this way you can quickly and easily access precisely the information you
need.
However, before you can use an SQL view you must create it and define exactly
which information you are interested in looking at, and where that information
is stored.
Visualizer SQL View makes things as easy as possible for you by offering you
three alternative ways to create an SQL view. This lesson discusses one of
these ways and makes a passing reference to another.
ΓòÉΓòÉΓòÉ 6. Tutorial Review ΓòÉΓòÉΓòÉ
Reviewing the SQL View Tutorial
You should now feel confident about using an existing SQL view object to look
at data in a database, and creating a new SQL view object based on an existing
SQL view. You should also have an insight into creating new SQL view objects in
other ways.
Understand what you did?
If you feel you did not understand all you did, consider going through the
lessons again. Next time, double-click on all of the (Why?...) fields for
lesson explanations and on all of the highlighted text fields for conceptual
information.
For more information
You can find conceptual, control and task information in the Visualizer online
help and in Visualizer Query for OS/2: Using, SH45-5089-00. An online version
of this book is also provided in your Manuals folder.
What to do now
You have now completed the SQL View tutorial.
If you would like to repeat the tutorial, select here on the back-page button:
Alternatively close the tutorial window by double-clicking on the title-bar
mini icon.
ΓòÉΓòÉΓòÉ <hidden> ΓòÉΓòÉΓòÉ
This is a footnote window. The highlighted terms in this tutorial are usually
displayed in larger windows. Press the escape key on your keyboard to close the
footnote.
ΓòÉΓòÉΓòÉ <hidden> ΓòÉΓòÉΓòÉ
This is a footnote window. Why information is usually displayed in larger
windows.