Virtual fields

A virtual field is not a column in a table and it is not used to store data: it is used to display data from another module.

Loan Supervisor: (Loan Information) in the Loans module is an example of a virtual field: it is an attachment field which displays Summary Data (SummaryData) of a record in the Parties module. The Summary Data is not itself stored in the Loans module. What is stored in a reference field hidden from the user is the IRN of the attached Parties record.

For example, a record in the Loans module attaches to a record in the Parties module (the loan supervisor) via the Loan Supervisor: (Loan Information) field. SummaryData from a Parties record displays in the Loan Supervisor: (Loan Information) field.

In an attachment there is a reference column in the Primary module (the module from which the attachment is made) which stores the IRN of the attached record. This column is hidden from users. Data from the attached record does display in a virtual field (the virtual field points to the hidden reference field which points to the attached record in the Parties module).

In this example, the Loan Supervisor: (Loan Information) field is a virtual field called InfLoanSupervisor, and it points to a reference field called InfLoanSupervisorRef, which in turn points to the SummaryData field in an attached record in the Parties module.

When a search is made of a virtual field, two Also Searches may take place. In this Loans example:

1. An Also Search Registry entry for InfLoanSupervisor can specify additional fields in the Loans module to be searched.
2. If there is an Also Search Registry entry for SummaryData in the Parties module (the column referenced by InfLoanSupervisor), a search of InfLoanSupervisor in the Loans module will also search the Parties module columns listed in the Also Search Registry entry for SummaryData.