WebFOCUS
Online Help > Creating Charts With Graph Tools > Creating Graphs With Advanced Graph Assistant > Working With Joins
A join is a temporary connection between two or more
data sources that share at least one common field. After you join
two data sources, each time WebFOCUS retrieves a record from the
first data source (host file), it also retrieves the matching records
from the second data source (target file).
Advanced Graph Assistant provides a graphical method for creating
and manipulating joins. You can also create define-based joins and
multi-field joins.
Procedure: How to Create a Join
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Click
the Data selection tab.
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Click
the Join tab, located to the right of the
Available Fields tab.
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Click
the Join
button.
The Please pick a target master file dialog box opens.
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Select a Master File and click OK.
The Create
Join dialog box opens, as shown in the following image.
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In the
Description box, give the join a meaningful and unique name.
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Select
one of the following join Type options:
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Default. For
an existing join. Utilizes the existing join type.
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Inner. An
Inner join omits the source file rows that lack corresponding rows
in the target file.
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Left Outer. A
Left Outer join extends the results of an Inner Join and retrieves records
from both the source and target files. This type of join includes
all records from the source file and any records from the target
file where the condition values match. If there are no matching
values in the target file, the join still retrieves records from
the source file.
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Select one of the following join Instances
options:
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Multiple. A Multiple Instances
join is a one-to-many join structure that matches one value in the
source file to multiple values in the target file.
For example, joining the employee ID
field in an employee data source to the employee ID field in a company
training data source that lists all training classes offered to employees
would result in a listing of all courses taken by each employee,
or a joining of the one instance of each ID in the source file to
the multiple instances of that ID in the target file.
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Single. A Single Instance join
is a one-to-one join structure that matches one value in the source
file to one value in the target file.
For
example, joining the employee ID field in an employee data source
to an employee ID field in a salary data source would result in
a single instance of salary data for each employee ID.
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Select
an appropriate indexed field from the source file using the Select
a source field drop-down list below the Source Fields heading. You
can also select multiple indexed fields from the source file when
creating a multi-fields join.
Note: Fields from the source and target files must
have the same format and be indexed fields in order to use them
to create joins. Indexed fields are identified by the key
icon.
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Select
an appropriate indexed field from the target file using the Select
a target field drop-down list below the Target Fields heading.
Note: If you selected a field from the source file
that does not have a matching indexed field with the same format
in the target file, the message 'There were no fields found" is
displayed instead of a Target Fields drop-down list.
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To see
the join syntax, click the View JOIN Syntax button,
then click OK.
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Click
the Save & Create button to create the
join.
The new join appears in the Joins list.
Procedure: How to Create a Define-based Join
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Click the Data selection tab.
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Click the Available Fields tab,
located below the Data selection pane.
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Click the down arrow to the right of
the define
button.
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Click the New define field option.
The Field Creator dialog box opens,
as shown in the following image.
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Create
a defined field by typing a name in the Field box, creating the
desired function or expression in the input area, selecting the
desired Format, and clicking OK.
The new define field, prefixed with the function symbol
icon,
appears in the Available Fields list.
If you want to delete
or edit an existing define, select the define field, click the down arrow
next to the define icon, and select one of the options, as shown
in the following image.
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Add
the defined field when creating a join. For details, see How to Create a Join.
Note: Fields must have the same format and be indexed
fields in order to use them to create joins.
Procedure: How to Delete a Join
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Data
selection tab.
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Click
the Joins tab below the Data selection pane.
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Select
the join you want to delete.
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Click
the X (delete) button above.
Procedure: How to Edit a Join
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Click
the Data selection tab.
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Click
the Joins tab below the Data selection pane.
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Double-click
the join you want to edit.
The Create Join dialog box opens.
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Make
the desired edits to the join.
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Click
the Save & Create button to save the
edited join.