When I was checking the 'Account Name' field in Contact Object it is appearing as a 'Lookup(Account)

Question

When I was checking the Account Name field in Contact Object it is appearing as a Lookup(Account) account is parent and contact is child i know those relation ships and behavior
parent to child query ex: account ac =[select id,name ,(select id,anme from contacts) from account]; same like contact is parent and Opportunity child but query from different

List<contact> consobj=[SELECT id,firstname,(SELECT OpportunityId FROM OpportunityContactRoles) ,lastname FROM contact ];

what is difference between Account/Contact and Contact/Opportunity

Answer 1

The difference basically lies in how both account and opportunities are related to each other.

Salesforce allows to capture only once account per contact object, which seems legit, its a rare possibilty that a contact is related to multiple Accounts. So we have one-to-many relationship between Account and Contact, viz. one Account can have multiple contacts, but one contact can be associated with only one Account.

Now coming to, opportunityContactRole. It is a junction object between Opportunity and Contact. There is a many-to-many relationship between Opportunity and Contact, through a junction object alled OpportunityContactRole. In an opportunity, you may add many opportunity contact roles and reverse is also true

Hope this clarifies your query.