After you create a mapping model from models in the Data Project Explorer
view, follow these steps to run the discover function to find relationships
between the elements of the schemas that are displayed in the mapping editor.
- In the Data Project Explorer view, expand the current project, mytestproject.
- Expand the Mappings folder.
- Double-click the myfirstmapping.msl mapping model that you created in the last exercise to open the three-paned mapping editor.
- To model the integration between two schemas (these schemas could represent two separate
data sources), create a mapping between columns in the two tables that
you think are similar. In this example, you assume that you know of a project
number relationship between the columns MGRNO in the DEPARTMENT table,
and the MAJPROJ column in the PROJECT table. Select the MGRNO column in
the DEPARTMENT table in the Source pane, and select the MAJPROJ column
in the PROJECT table in the Target pane.
- Right-click anywhere in the mapping editor, and select Create Mapping. The editor displays a mapping line between the two columns with a hub
that appears as a square.
- You can also use the discover function to find relationships between the
source and the target. Select the DEPARTMENT table in the Source pane, and select the PROJECT table in the Target pane.
- Right-click in the center pane of the mapping editor.
First, configure the discover function to use the Lexical similarity and Semantic name algorithms, because this matches the source and target elements by using name or text values.
- Select Discover Relationships-> Advanced Configuration.
- In the table of algorithms, select Lexical similarity and Semantic name. These algorithms search text and names to find matches.
- Specify the Composition by sequence radio button, which ensures that the Lexical similarity algorithm is used
before the Semantic name algorithm. Since that is the current sequence,
you do not need to change the order of the algorithms.
- Click Finish.
Then, run the discover function to find the most satisfactory match among
all of the elements in the model.
- Right-click in the center pane of the mapping editor.
- Select Discover Relationships-> Find Best Fit.
- On the Specify Scope to Discover Relationships page, select the scope of
the discover function.
All of the elements from both the source and the target tables are selected,
because you launched the discover function from the center pane of the
mapping editor. The scope changes depending on how you start the discover
function. You can clear a check box to exclude that element from finding
the relationships. For this example, leave all of the elements selected.
- If you do not want to see this window again, select the Do not show this window again while looking for relationships check box. For this example, do not select the check box.
- Click Finish.
- The mapping editor view displays the mapping lines between the successful
matches. These are proposed or discovered mappings. Notice that the hubs
of the discovered mappings appear as brackets. Select the mapping line
between the DEPTNO column in the DEPARMENT table, and the DEPTNO column
in the PROJECT table. Right-click the line and select Accept Mapping.
Notice that the color of the line and the hub of the line changed when you accepted the proposed mapping.
- Right-click in the center pane of the mapping editor and select Reject All Mappings. The accepted mapping and the manually created mapping both remain in
the editor.