How to: |
Cluster joins enable you to create a new file structure by linking existing synonyms of two or more relational tables using the same or mixed data sources. For example, you may join a DB2 table and an Oracle table, and so on. Use cluster joins to create new views in the metadata by linking together physical tables and easily report against the new view or structure. You can create cluster joins by using the Modeling View of the Synonym Editor.
The Master File that is created combines the fields of the joined tables within a single file. The Access File from the combined file contains information about the actual location of the data sources and the Join information. It also shows how the tables are linked.
The total number of tables that you can add to the tool is 64 (using 63 joins), which results in a new Master File that has a maximum of 64 segments.
The Cluster Join Tool enables you to create a Star Schema which consists of a fact table referencing a number of dimension tables. Optionally, you can also create a view that has more than one fact table.
Use the Modeling View to enhance an existing synonym by adding a segment.
The Synonym Editor opens.
The Synonym Editor Modeling View tab opens in the workspace.
The following pop-up menu appears.
Select a synonym to be inserted and click Select.
Note: Use this method if you are creating a cluster join with an existing table or synonym.
Tip: Click Save As from the Modeling View File menu if you want to modify the original synonym.
When this option is selected, you are first presented with the Adapter dialog where you can select a configured adapter connection to continue or configure a new adapter, if necessary.
The following image is an example of a screen that appears where you provide information for the connection parameters.
The following image is an example of a screen that enables you to select tables to create synonyms.
The selected synonyms will be created and added to the Modeling View.
Note: Use this method if you are creating a cluster join and need to use a synonym that does not exist. This option enables you to create the synonym and continue to create the cluster join.
Note: Use this method if you are coding a new Master File, as you would for a FOCUS data source.
The segment is added in the Modeling View.
Note: These join options are not available, and do not appear, for FOCUS tables. The only way to view these options are by using relational tables.
Note: Join All is the default option.
Note: Outer joins are subdivided into Left Outer Joins, Inner Joins, or Cross Joins.
Use the Tree and Text View tabs of the Synonym Editor to view or edit the details of these tables (segments).
Tip: Click Save As from the Modeling View File menu if you do want to modify the original synonym.
Another way to create a cluster join is to start with an empty synonym:
The Synonym Editor opens.
WebFOCUS |