Discovery Guide > Using and Configuring Discovery > Enabling Multicolumn Relationship Discovery
 
Enabling Multicolumn Relationship Discovery
You can configure Discovery to search for multicolumn relationships between tables. This increases the amount of time required by relationship discovery, but it could be important depending on your data. By default, Discovery searches only for single-column relationships. See About Multicolumn Relationships for more information about configuring Discovery for multicolumn relationship discovery.
To configure Discovery to search for multi-column relationships
1. From the Administration menu, choose Configuration.
2. In the Configuration dialog, expand the Discovery/Relationship/MultiColumnKey branch.
3. Select Allow Multicolumn Key and change the value to True.
4. Adjust any of the other multicolumn configuration parameter values described below:
Configuration Parameter
Default
Use to...
Allow Multicolumn Key
False
True—The Discovery Relationship Scanner searches for multicolumn keys. The width of multicolumn key is set in Maximum Columns for Multicolumn Key.
False—Only single-column relationships are discovered.
Check Only Many-to-Many Relationships
True
True—The multicolumn keys are only composed from many_to_many relationships. Doing this removes the combinations many-to-one and one-to-many to form a multicolumn key.
False—All combinations are checked for relationships. This is more accurate but could take much longer.
Combine Multicolumn Relationships
True
True—Multicolumn relationships between two tables with score over 95 are consolidated into one relationship line on the Model diagram if more than five multicolumn relationships are discovered.
False—All individual relationship lines are displayed on the Model diagram.
Maximum Columns for Multicolumn Key
3
The maximum number of columns for creating a multicolumn key. This value is used if Allow Multicolumn Key is True. This value can only be greater than or equal to 2. If this number is too large, Discovery tasks can run a very long time, so use caution when increasing this number.
Maximum Keys to Be Checked for Multicolumn Key
1000
The maximum number of keys to check for possible multicolumn keys between two tables. This value is used if Allow Multicolumn Key is True. If this value is large, it checks more combinations of multicolumn keys. However, it might run out of memory more easily.
5. Click OK to apply your configuration changes.
When a relationship is formed by multiple columns, it is indicated as a multicolumn relationship on the model’s Relationships tab. See Working with the Relationships Tab, for more information.