我有一个子文档数组，如下所示
/* record 1 */
{
"_id" : "462044",
"program" : [
{
"name" : "Business Services"
},
{
"name" : "Homeland Security"
},
{
"title" : [
"associate"
],
"name" : "Engineering"
},
{
"title" : [
"associate"
],
"name" : "Computer Software"
}
]
}
/* record 2 */
{
"_id" : "462045",
"program" : [
{
"name" : "Business Services"
},
{
"name" : "Homeland Security"
},
{
"title" : [
"associate"
],
"name" : "Engineering"
},
{
"title" : [
"associate"
],
"name" : "Computer Software"
}
]
}
[我想删除没有＆＃39;标题＆＃39;子构件]
如何编写mongo update query或nodejs函数以获取以下文档集
/* record 1 */
{
"_id" : "462044",
"program" : [
{
"title" : [
"associate"
],
"name" : "Engineering"
},
{
"title" : [
"associate"
],
"name" : "Computer Software"
}
]
}
/* record 2 */
{
"_id" : "462045",
"program [
{
"title" : [
"associate"
],
"name" : "Engineering"
},
{
"title" : [
"associate"
],
"name" : "Computer Software"
}
]
}
答案 0 :(得分：0)
嗯，首先你的文档结构看起来很奇怪。在您的案例school1和school2中，每条记录都有一个不同的字段代表基本相同的信息。
如果您将这些字段重命名为school，则可以轻松修复。
如果您修复了文档结构，则可以借助聚合框架和纯更新查询轻松删除所需的子文档。
示例：
db.collection.aggregate([
{
$project: {
school: {
$filter: {
input: "$school.program",
as: "prog",
cond: {
$ne: [
{
$ifNull: [
"$$prog.title",
true
]
},
true
]
}
}
}
}
}
]).forEach(function(o){
db.collection.updateOne({
_id: o._id
},
{
$set: {
school: o.school
}
});
})
这会将您的旧文档转换为（删除所有不包含title的程序的子字段：
{
"_id" : ObjectId("57371cdf81e9959ba1a5fab0"),
"school" : [
{
"title" : [
"associate"
],
"name" : "Engineering"
},
{
"title" : [
"associate"
],
"name" : "Computer Software"
}
]
}
{
"_id" : ObjectId("57371cdf81e9959ba1a5fab1"),
"school" : [
{
"title" : [
"associate"
],
"name" : "Engineering"
},
{
"title" : [
"associate"
],
"name" : "Computer Software"
}
]
}