A powerful way to study database data is to navigate between the tables
in a schema by following table relationships declared by primary and
foreign keys. DbVisualizer includes a Navigator feature for this
purpose, visualizing the relationships graphically while making the
data for each navigation case easily accessible in a data grid.
To launch the Navigator
the table you want to start the navigation from in the Database Objects
Tree, and then open the Navigator tab in the Object View.
Navigator tab showing the initial table
The Navigator has two parts: a graphical view and a data grid.
Initially, the graphical view shows just the selected start
and the data grid shows the data for the start table.
The data grid is of the same type as you encounter in
other parts of DbVisualizer, but extended with a Related Table list and
a Tag button. You can learn more about the general data grid in the Data
section of the Getting
chapter. The Navigator specific extensions are described in detail in
the following section.
Data navigation in DbVisualizer means following table relationships
declared by primary and foreign keys, using a unique key value. In the
example schema shown in the screen shots in this section, there is a
table named DEPARTMENTS with a primary key named DEPARTMENT_ID. Another
table named EMPLOYEES has a foreign key constraint, declaring that
values in its DEPARTMENT_ID column refer to primary key values in the
column with the same name in the DEPARTMENTS table.
Related Table list
If you use DEPARTMENTS as you start table, you can easily navigate to
the EMPLOYEES table for different DEPARTMENT_ID values. In the data
grid, select one or more columns in the row that holds the
DEPARTMENT_ID you want to use for navigation. In the figure above, the
DEPARTMENT_NAME column in the row for DEPARTMENT_ID = 60 is selected.
Next, bring up the Related Table list. It lists all tables the
DEPARTMENTS table is related to through primary and foreign keys, with
the key columns within parenthesis. A forward arrow (->) between
the table names means that the DEPARTMENTS table has a foreign key
relation to the named table. A backward arrow (<-) means that
named table has a foreign key relation to the DEPARTMENTS table.
Navigation from DEPARTMENTS to EMPLOYEES for DEPARTMENT_ID = 60
When you select "DEPARTMENTS (DEPARTMENT_ID) <- EMPLOYEES
(DEPARTMENT_ID)" in the
Table list, a node is added to the graph for the EMPLOYEES table, with
an arrow from the DEPARTMENTS table node to show the navigation
direction. We call this a navigation
The EMPLOYEES node contains the key columns (just one in this example)
and their values.
The arrow between the nodes is labeled with the key column name. In
addition, the arrow label also shows the name and value of the column
that you selected in the DEPARTMENTS table when you created this
navigation case, i.e., the DEPARTMENT_NAME column. If you select
multiple columns when you create a navigation case, all non-key column
names and values are included in the arrow label. This can make it
easier to see at a glance what a navigation case represents.
The grid is also updated when you create a navigation case, to show all
rows in the table you navigated to that has a key value corresponding
to the selected key value in the table you navigated from. In this
case, it shows all rows in the EMPLOYEES table with DEPARTMENT_ID equal
You can edit the grid values, but be aware that if you change the value
of a key in the grid for a navigation case, the row will disappear from
grid since the grid only shows rows with keys matching the navigation
case key value.
You can continue to create more navigation cases from any node
the graph. For instance, if the schema contains a table with job
history information for employees, you can navigate to the history for
from the EMPLOYEES node. Or, you can select the DEPARTMENTS node in the
graph to navigate to the EMPLOYEES table for a different department.
Just click on the DEPARTMENTS node, select another row in the data grid
and then the same Related Table list entry.
If you want to create multiple navigation cases from one table to
another using the same relationship, you can select columns in multiple
rows in the first table. When you make a selection in the Related Table
list, one navigation case per row is created.
Every time you select a node in the graph, the data grid is updated to
show the corresponding data. The grid settings for one node are
independent of the settings for another node. For instance, if
define a filter for one node, the filter is only associated with the
grid for that node.
Context Information to the Graph
The navigation node always shows the key columns and their values, but
sometimes you may want to add other columns to the node to better
describe what it represents. This is called tagging
There are two ways to do so: drag and drop cells from the grid to any
node, or use the Tag
button in the grid toolbar to tag the currently selected node
with the currently selected cells in the grid.
To drag and drop cells to a node, select one or more cells in the grid.
With the left mouse button pressed and the mouse positioned over one of
the selected cells, drag the cells over a node in the graph and release
the mouse button. The cells are added to the node.
Figure: A node
tagged with additional column values
Alternatively, you can select the cells in the grid and click on the Tag
) to add the cell values to the
currently selected node.
As you add navigation cases, you may find that you need to move nodes
around, remove selected nodes, zoom and move around in the graph, etc.
You can rearrange the layout of the graph by selecting a node and, with
the left mouse button pressed, drag it around. The arrow and its label
moves with the node.
The toolbar for the graph offers a number of tools to help you with
tasks can also be accessed through the graph pop-up menu.
||Clicking the Reload
button removes all navigation cases, leaving just the node for the
table you started with.
||You use the
Show/Hide Controls button to control the display of an
Overview control, see below.
In button lets you zoom into the graph, one step per click.
Out button zooms the graph out one step with each click.
|The Zoom Selected Area button
zoom the currently selected node.
||Clicking the Zoom
100% button zooms the graph so that all items are shown
with their standard size.
|Toggle the Magnifying Mode. When
enabled, the content around the mouse pointer is magnified
||Use the Fit
button to make all graph items fit in the graph display area.
lays out all graph item with standard positions, distances between
items, etc. This can be useful after making manual changes, such as
removing nodes or tagging nodes.
Node button removes the selected node. It is only enabled
when a navigation case node is selected.
|Toggle between Navigation and Edit
Modes. With Navigation Mode enabled, you can move the graph
content with the left mouse button depressed.
The Overview control is useful for large graphs that do not fit into
the display area.
with the Overview Window displayed
The gray area in the Overview control indicates the portion of the
graph that is currently shown in the display area. You can drag the
gray area around to study other portions of the graph.
To get a larger graph display area, you can put the Overview control in
a separate window. Just uncheck the Docked checkbox.
and Printing the Graph
You can also export the graph to an image file or print it. Use the
corresponding toolbar buttons to do this.
|| Export the graph to a file in JPG, GIF, PNG, SVG or PDF
||Print the graph
||Show a preview of how the graph will be printed
When you print the graph, you are prompted for information about what
to print (the Graph or the View, i.e., just the portion visible in the
display area) and how many rows and columns to split the printing over
(one page is used for each row/column). See the Export and Import
and the Print
section in the Getting
chapter for details.
Opening the Navigator
from the Data tab
Sometimes, you may realize that you want to analyze the relationships
for a table when you are working with it in the Data tab. If you have
configured the Data tab to show only filtered data, sorted in a
specific way, etc. opening the Navigator tab and making all the same
configurations there may be a bit of a hassle. A more convenient way is
to just pick Show in Navigator
in the right-click menu in the Data tab. It opens the table in the
Navigator tab with all the same configurations as you made in the Data
Copyright © 2012 DbVis Software AB. All rights reserved.