Loosely coupled Tightly coupled Max number of lookup is 25 Max number of master is 2 Not a mandatory Mandatory Once value is assigned can be changed Cannot be changed Partent delete child cannot delete parent delete child also delete cannot on lookup Roll up can be made on master-detail
The Wide World of Object Relationships There are two main types of object relationships: lookup and master-detail.
Lookup Relationships In our Account to Contact example above, the relationship between the two objects is a lookup relationship. A lookup relationship essentially links two objects together so that you can “look up” one object from the related items on another object. Lookup relationships can be one-to-one or one-to-many. The Account to Contact relationship is one-to-many because a single account can have many related contacts. For our DreamHouse scenario, you could create a one-to-one relationship between the Property object and a Home Seller object.
Master-Detail Relationships While lookup relationships are fairly casual, master-detail relationships are a bit tighter. In this type of relationship, one object is the master and another is the detail. The master object controls certain behaviors of the detail object, like who can view the detail’s data. For example, let’s say the owner of a property wanted to take their home off the market. DreamHouse wouldn’t want to keep any offers made on that property. With a master-detail relationship between Property and Offer, you can delete the property and all its associated offers from your system
Loookup : Master :
Loosely coupled Tightly coupled
Max number of lookup is 25 Max number of master is 2
Not a mandatory Mandatory
Once value is assigned can be changed Cannot be changed
Partent delete child cannot delete parent delete child also delete
cannot on lookup Roll up can be made on master-detail
Create Object Relationships (https://trailhead.salesforce.com/en/modules/data_modeling/units/object_relationships)
The Wide World of Object Relationships
There are two main types of object relationships: lookup and master-detail.
Lookup Relationships
In our Account to Contact example above, the relationship between the two objects is a lookup relationship. A lookup relationship essentially links two objects together so that you can “look up” one object from the related items on another object.
Lookup relationships can be one-to-one or one-to-many. The Account to Contact relationship is one-to-many because a single account can have many related contacts. For our DreamHouse scenario, you could create a one-to-one relationship between the Property object and a Home Seller object.
Master-Detail Relationships
While lookup relationships are fairly casual, master-detail relationships are a bit tighter. In this type of relationship, one object is the master and another is the detail. The master object controls certain behaviors of the detail object, like who can view the detail’s data.
For example, let’s say the owner of a property wanted to take their home off the market. DreamHouse wouldn’t want to keep any offers made on that property. With a master-detail relationship between Property and Offer, you can delete the property and all its associated offers from your system
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