belongsToMany
A belongsToMany
relationship is a many-to-many
relationship. For instance, a User
may have multiple Permissions
while a Permission
can belong to multiple Users
.
The first value passed to belongsToMany
is a WireBox mapping to the related entity.
belongsToMany
makes some assumptions about your table structure. To support a many-to-many
relationship, you need a pivot table. This is, at its simplest, a table with each of the foreign keys as columns.
As you can see, Quick uses a convention of combining the entity table names in alphabetical order with an underscore (_
) to create the new pivot table name. If you want to override this convention, you can do so by passing the desired table name as the second parameter or the table
parameter.
Quick determines the foreign key of the relationship based on the entity name and key values. In this case, the User
entity is assumed to have a userId
foreign key and the Permission
entity a permissionId
foreign key. You can override this by passing a foreignKey
in as the third argument and a relatedKey
as the fourth argument:
Finally, if you are not joining on the primary keys of the current entity or the related entity, you can specify those keys using the last two parameters:
The inverse of belongsToMany
is also belongsToMany
. The foreignKey
and relatedKey
arguments are swapped on the inverse side of the relationship.
If you find yourself needing to interact with the pivot table (permissions_users
) in the example above, you can create an intermediate entity, like UserPermission
. You will still be able to access the end of the relationship chain using the hasManyThrough
relationship type.
attach
Use the attach
method to relate two belongsToMany
entities together. attach
can take a single id, a single entity, or an array of ids or entities (even mixed and matched) to associate.
detach
Use the detach
method to remove an existing entity from a belongsToMany
relationship. detatch
can also take a single id, a single entity, or an array of ids or entities (even mixed and matched) to remove.
sync
Sometimes you just want the related entities to be a list you give it. For these situations, use the sync
method.
Now, no matter what relationships existed before, this Post
will only have three tags associated with it.
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