[英]Validate embedded document in mongodb
I'd like to validate my documents in MongoDB. 我想在MongoDB中验证我的文档。 As described here , the validator query can be specified during the
createCollection
command. 如所描述的在这里 ,可以在过程中指定的验证查询
createCollection
命令。
My application is a simple todo list, so the collection list
has many documents like this: 我的应用程序是一个简单的待办事项列表,因此收集
list
包含许多这样的文档:
{
"name": "the list name",
"color: "red",
"items": [
{
"title": "item1",
"isDone": false,
"text": "the item description"
}
]
}
How can I sure that all documents has this shape? 如何确定所有文档都具有这种形状?
EDIT: I'm using MongoDB 3.4 编辑:我正在使用MongoDB 3.4
You can't. 你不能
There's no way to avoid new property. 没有避免新财产的方法。 If this needed is required, you should consider to migrate a SQL solution.
如果需要此要求,则应考虑迁移SQL解决方案。
Otherwise, your document will contain at least those members and those members will be validated. 否则,您的文档将至少包含那些成员,并且这些成员将被验证。
I assume that all fields are mandatory, so no list can be added neither without a color nor having an item without a title. 我假设所有字段都是必填字段,所以没有颜色的列表和没有标题的项目都不能添加。
I assume that color is an enum also. 我认为颜色也是一个枚举。
{
validator: {
name: { $type: 'string', $exists: true },
color: { $in: ['red', 'green', 'blue'], $exists: true },
items: { $exists: true },
$or: [
{ items: { $size: 0 } },
{
$and: [
{ 'items.0': { $exists: true } },
{
items: {
$not: {
$elemMatch: {
$not: { $type: 'object' }
}
}
}
},
{
items: {
$not: {
$elemMatch: {
$or: [
{ title: { $not: { $type: 'string' } } },
{ title: { $not: { $exists: true } } },
{ isDone: { $not: { $type: 'bool' } } },
{ isDone: { $not: { $exists: true } } },
{ text: { $not: { $type: 'string' } } },
{ text: { $not: { $exists: true } } }
]
}
}
}
}
]
}
]
}
}
Explanation 说明
The solution is based on the second-order logic . 该解决方案基于二阶逻辑 。 Indeed, the assertion "all elements have to match A" is equal to "no element should match !A" or, if you have many queries, "all element have to match A and B" becomes "no element should match !A or !B", where
!
实际上,断言“所有元素都必须匹配A”等于“没有元素应该匹配!A”,或者,如果您有许多查询,“所有元素必须匹配A和B”变为“没有元素应该匹配!A或B”。 !B”,在哪里
!
means the negation of the following predicate. 表示以下谓词的否定。
Long explanation 详细说明
The first two query items assert that all documents have name
and color
, the third one the items
property always exists. 前两个查询项目断言所有文档都具有
name
和color
,第三个查询items
属性始终存在。 NB: in the third query property, there's not the $type
check because mongodb treats the array
type in a odd way . 注意:在第三个查询属性中,没有
$type
检查,因为mongodb 以奇怪的方式处理array
类型。
The $or
operation below is needed because the item
property can be empty or filled with some data. 需要下面的
$or
操作,因为item
属性可以为空或可以填充一些数据。
First clause of $or
checks if the array is empty. $or
第一个子句检查数组是否为空。 If the array is not empty, three checks should be done: 如果数组不为空,则应进行三项检查:
So the first $and
operator element checks that at least one element is present. 因此,第一个
$and
运算符元素检查是否存在至少一个元素。 The second one checks that all array elements are objects. 第二个检查所有数组元素都是对象。 The third one asserts that all objects have a specified shape.
第三个断言所有对象都具有指定的形状。
In mongodb, there's an operator for checking if all array elements match a query. 在mongodb中,有一个运算符用于检查所有数组元素是否与查询匹配。 So, using the second order logic, the check should be turned over.
因此,应使用二阶逻辑将检查移交。
In fact, the last two clauses of $and
check that no elements match none of the described query. 实际上,
$and
的最后两个子句检查没有元素与所描述的查询匹配。 Each sub query is the negate of a wanted query. 每个子查询都是所需查询的否定项。
Example 例
fails 失败
{ name: 'foo' }
{ color: 'red' }
{ color: 'unknown color' }
{ name: 'foo', color: 'red' }
{ name: 'foo', color: 'red', item: 3 }
{ name: 'foo', color: 'red', item: [ 3 ] }
{ name: 'foo', color: 'red', item: [ { } ] }
{ name: 'foo', color: 'red', item: [ { title: 'ww' } ] }
{ name: 'foo', color: 'red', item: [ { title: 'ww', isDone: false } ] }
{ name: 'foo', color: 'red', item: [ { title: 44, isDone: false, text: 'the text' } ] }
pass 通过
{ name: 'foo', color: 'red', items: [ ] },
{ name: 'foo', color: 'red', items: [ ] },
{ name: 'foo', color: 'red', items: [ { title: 'the title', isDone: false, text: 'the text' }, { title: 'the title1', isDone: true, text: 'the text' } ] }
This solution is still valid using MongoDB 3.2 该解决方案在MongoDB 3.2上仍然有效
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