如何选择包含关联的字段? [英] How to select fields of a contained association?
问题描述
我想执行以下查询,其中我只想从关联中读取必要的字段。
我在 select()中使用了一个点符号
下面更好地解释我想要什么。
基本上 select()
似乎关心用户
。是否可以指定 Sites
?
$ orders = $ this-> Orders-> find()
- > contains([
'Sites.Users'=> function($ q){
return $ q
- > select([
'Sites.id',
'Sites.user_id',
'Users.id',
'Users.name',
'Users.owner_id',
'Users.firstname',
'Users.lastname'
])
- > autoFields(false);
},
])
- > first();
您必须单独配置容器,其他包含将不起作用。
确切地说,不能从相应的包含配置之外的任何地方选择包含的字段,唯一的例外是 belongsTo / hasOne
使用连接策略的关联,可以在 select()
调用立即数父查询,因为这些关联将通过该查询中的联接检索。
如果 Sites
将是 belongsTo
关联,那么您可以通过 select()
调用订单
。如果 Users
将是 belongsTo
,但 Sites
code> hasMany ,则可以使用 select()
调用 Sites
为 Users
选择字段。
话虽如此,在你的情况下你要么使用 queryBuilder
选项定义嵌套数组结构中的回调
'sites'=> [
'queryBuilder'=> function($ q){
return $ q
- > select([
'Sites.id',
'Sites.user_id'
]);
},
'Users'=> function($ q){
return $ q
- " select([
'Users.id',
'Users.name',
'Users.owner_id',
'Users.firstname',
' Users.lastname'
]);
}
]
])
b $ b
或者,如果您实际上不需要查询构建器,请使用字段
选项
contains([
'Sites'=> [
'fields'=> [
'Sites.id',
'Sites.user_id'
],
'Users'=> [
'fields'=> [
'Users.id',
'Users.name',
'Users.owner_id',
'Users.firstname',
'Users.lastname'
]
]
]
])
另请参阅
- Cookbok>数据库访问& ORM>查询生成器>将条件传递给包含
- API> \Cake\ORM\QueryBuilder :: contain()
I would like to execute the following query where I'd like to read only the necessary fields from associated.
I used a dot notation in select()
below to better explain what I want.
Basically the select()
seems to concern Users
only. Is it possible to specify the fields of Sites
?
$orders = $this->Orders->find()
->contain([
'Sites.Users'=> function ($q) {
return $q
->select([
'Sites.id',
'Sites.user_id',
'Users.id',
'Users.name',
'Users.owner_id',
'Users.firstname',
'Users.lastname'
])
->autoFields(false);
},
])
->first();
You have to configure the containments individually, selecting fields for other containments won't work.
To be exact, you cannot select fields for a containment from anywhere else than the corresponding containment configuration, with the only exception of belongsTo/hasOne
associations that are using the join strategy, fields for them can be selected in the select()
call of the immediate "parent" query, as these associations are going to be retrieved via a join in that query.
If for example Sites
would be a belongsTo
association, then you could select the fields for it via the select()
call on Orders
. If Users
would be a belongsTo
, but Sites
a hasMany
, then you could use the select()
call for Sites
to select fields for Users
.
That being said, in your case you either use the queryBuilder
option to define callbacks in a nested array structure
contain([
'Sites' => [
'queryBuilder' => function ($q) {
return $q
->select([
'Sites.id',
'Sites.user_id'
]);
},
'Users' => function ($q) {
return $q
->select([
'Users.id',
'Users.name',
'Users.owner_id',
'Users.firstname',
'Users.lastname'
]);
}
]
])
or, if you don't actually need the query builder, use the fields
option
contain([
'Sites' => [
'fields' => [
'Sites.id',
'Sites.user_id'
],
'Users' => [
'fields' => [
'Users.id',
'Users.name',
'Users.owner_id',
'Users.firstname',
'Users.lastname'
]
]
]
])
See also
- Cookbok > Database Access & ORM > Query Builder > Passing Conditions to Contain
- API > \Cake\ORM\QueryBuilder::contain()
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