"Who knows who" relations for Salesforce Contact and Accounts - part 1: How this works

Sometimes we need to store information about Contact-Contact, Account-Contact, Account-Account relations:

• User knows Contact and Account
• Contact is employee of a Company;
• Account is Employer of a Contact;
• Contact is former employee of a Company;
• Account is former Employer of a Contact, etc.

For this purpose we used Custom object "Who Knows Who":

The records can be created manually and automatic. After insert "Who Knows Who" record fires trigger which inserts "reverse" record.

Automatic scenarios

User "knows" Account and created Contact
When new Contact created, new "Who Knows Who" record is inserted:

Contact related lists:

This Contact and Company related to User:

The user who creates this Contact "knows" it and Contact's Company (reverse record).

"Known" Contact("User" field - lookup to User):

Employer - Former Employer
When Contact reassigned to other Account, insert 2 "Who Know Who" records - "Employer" and "Former Employer": Account is Former Employer of Contact:

In left column information about Contact: current Contact's Company(Account field), and date of termination in previous company. Reverse record: In this way, information about Account's former employees stores in "Who Knows Who" related list. The account is the employer of Contact: Current Account stores info about former employer of Contact in "Who Knows Who" related list:

Manually scenarios

If you want to create a relation between some Contacts or Account, you can manually to insert "Who Knows Who" record and select kind of relationship in "Account relationship" and "Contact relationship" picklists.