belongsToThrough
A
belongsToThrough
relationship is the one
side of a many-to-one
relationship with an intermediate entity. It is used when you want to access a related, owning entity through one or more intermediate entities. For instance, a Post
may belong to a Team
via a User
.// Post.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function team() {
return belongsToThrough( [ "author", "team" ] );
}
function author() {
return belongsTo( "Post" );
}
}
// User.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function posts() {
return hasMany( "Post" );
}
function team() {
return belongsTo( "Team" );
}
}
// Team.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function members() {
return hasMany( "User" );
}
}
The only value needed for
belongsToThrough
is an array of relationship function names to walk through to get to the related entity. The first relationship function name in the array must exist on the current entity. Each subsequent function name must exist on the related entity of the previous relationship result. For our previous example, author
must be a relationship function on Post
. team
must then be a relationship function on the related entity resulting from calling Post.author()
. This returns a belongsTo
relationship where the related entity is User
. So, User
must have a team
relationship function. That is the end of the relationship function names array, so the related entity resulting from calling User.team()
is our final entity which is Team
.belongsToThrough( [ "author", "team" ] );
+----------------+---------------------------+----------------+
| Current Entity | Relationship Method Names | Related Entity |
+================+===========================+================+
| Post | author | User |
+----------------+---------------------------+----------------+
| User | team | Team |
+----------------+---------------------------+----------------+
This approach can scale to as many related entities as you need. For instance, let's expand the previous example to include an Office that houses many Teams.
// Post.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function office() {
return belongsToThrough( [ "author", "team", "office" ] );
}
function author() {
return belongsTo( "Post" );
}
}
// User.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function posts() {
return hasMany( "Post" );
}
function team() {
return belongsTo( "Team" );
}
}
// Team.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function members() {
return hasMany( "User" );
}
function office() {
return belongsTo( "Office" );
}
}
// Office.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function teams() {
return hasMany( "Team" );
}
}
belongsToThrough( [ "author", "team", "office" ] );
+----------------+---------------------------+----------------+
| Current Entity | Relationship Method Names | Related Entity |
+================+===========================+================+
| Post | author | User |
+----------------+---------------------------+----------------+
| User | team | Team |
+----------------+---------------------------+----------------+
| Team | office | Office |
+----------------+---------------------------+----------------+
HasOneThrough
relationships can be configured to return a default entity if no entity is found. This is done by calling withDefault
on the relationship object.// Post.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function team() {
return belongsToThrough( [ "author", "team" ] ).withDefault();
}
function author() {
return belongsTo( "Post" );
}
}
Called this way will return a new unloaded entity with no data. You can also specify any default attributes data by passing in a struct of data to
withDefault
.// Post.cfc
component extends="quick.models.BaseEntity" accessors="true" {
function team() {
return belongsToThrough( [ "author", "team" ] ).withDefault( {
"name": "No Team"
} );
}
function author() {
return belongsTo( "Post" );
}
}
Name | Type | Required | Default | Description |
relationships | array | true | | An array of relationship function names. The relationships are resolved from left to right. Each relationship will be resolved from the previously resolved relationship, starting with the current entity. |
relationMethodName | string | false | Current Method Name | The method name called to retrieve this relationship. Uses a stack backtrace to determine by default. |
Last modified 2mo ago