Access Route Considerations
Following are some important considerations when defining access routes:
- Access routes should always be defined in both directions, i.e. from table A to B and from table B to A.
- The Maximum Records parameter is important as it defines the cardinality of the table relationships. This parameter specifies the number of records that are expected to be found in the Accessed Table that have a key matching the Key Columns/Values. This value is only significant in that it is one or more than one. If it is one, then a 1:1 relationship between the tables is established, (for example, Employee works in a Department). If it refers to more than one, then a 1:many relationship is established. (For example, a Department has many Employees).
- Remember that access routes work both ways. If there is an access route from TABLE1 to TABLE2, then there should also be a corresponding access route from TABLE2 to TABLE1. For example, Department table has a 1:M relationship to the Employee table and the Employee table will have a 1:1 relationship to the Department table.
- When dealing with multiple parent-child relationships, it can be valuable to include access routes from the grandparent to the grandchild. These type of links are particularly useful to reporting tools like LANSA Client which can create a drill down report by following the access routes.
- Access routes are very useful for both developers and end users, in the case of LANSA Client. It is important to take the time to add access routes to your application databases.
- Access routes can be used with Other tables. They can be used to document the table relationships within your existing application databases.