Dependency Rules - trillium_discovery - Latest

Dependency rules define the many-to-one relationships between attributes (fields/columns) in a single data source. They consist of a left-hand side (LHS) which is composed of one or more attributes, and a right-hand side (RHS) composed of a single attribute.

In a dependency rule, the LHS attributes determines the RHS attribute, represented as LHSRHS.

For all dependency rules, the value in the LHS attribute(s) always determines the value in the RHS attribute. Certain dependency rules may be bilateral (LHSRHS AND LHSRHS), but only if the data supports this. The majority of dependency rules are LHSRHS only.

Example

Say you have the dependency CUSTOMER_ID CUSTOMER_NAME.

For the dependency to be 100% true, the unique value of CUSTOMER_ID should always result in the same value of CUSTOMER_NAME.

It is acceptable for different values of CUSTOMER_ID to identify the same CUSTOMER_NAME.

For example, CUSTOMER_ID CUSTOMER_NAME does not necessarily mean CUSTOMER_NAMECUSTOMER_ID.

While it is possible for a dependency to be bilateral, that is the value in the RHS attribute likewise determines the LHS attribute, the data must support this.