The procedure below shows how to configure mappings and an inner join
to output movies information with valid director IDs.
Procedure
Double-click the tMap component to open the map
editor.
The map editor shows three tables, named
row1,
row2 and
Valid_movies in this example,
corresponding respectively to the movies file
schema, the directors file schema, and the schema of
the output for valid movies information, and columns
in the row1 table are already
mapped to the columns in the
Valid_movies table.
Select the directorID column
in the row1 table, and drop it onto the
directorID column in the
row2 table to create a join
between the two input data sets based on the director
IDs.
Click the tMap
settings button, then click Value field for Join Model, and then click
the [...] button that
appears to open the Options
dialog box. In the dialog box, select Inner Join and click OK to define the join as an
inner join.
With this setting, only the movie records
with the director IDs matching with those in the
reference file will be passed to the output.
In the Schema
editor at the bottom of the map editor,
select directorID column of the
output schema, Valid_movies in this
example, and click the X
button to remove it.
Click the [+]
button beneath the output table to add a new column, name it
directedBy, set its length to
20, and move it up so that
it's between the title and
releaseYear columns.
Select the directorName
column in the row2 table, and drop it
to the Expression field
corresponding to the directedBy
column in the output table.
A new mapping is created between lookup
table and the output table.
Click OK to
validate the mappings and close the map editor, and click
Yes when asked
whether to propagate the changes.
The mapping configurations are saved and the
output schema is synchronized to the output
component tLogRow.
Press F6 or
click the Run button on
the Run view to execute
your Job.
Results
Only movie records with valid director information are
displayed on the Run
console.
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