Push deeply nested array
I am trying to figure out how I can insert a new item into a deeply nested array in mongodb. Take this structure for example:
{
name : "high school",
departments : [
{
name : "math",
courses : [
{
name : "algebra",
lessons: [
{
name: "algebra 1a",
students: [
{
name: "Dave",
id : "123456"
},
{
name: "alex",
id: "987654"
}
]
}
]
}
]
}
]
}
I know that I have to use $ when pushing a nested array like:
db.schools.update ({"departments.name": "math"}, {$ push: {"departments $ courses ..": X}})
But when trying to access a deeper array, it throws an error. How can I add a new lesson? or a new student?
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1 answer
Based on my research and understanding, it is currently not possible to do this in mongodb in a single operation. According to this JIRA ticket, this is desirable for an upcoming mongodb release.
Here's a tedious way to do what you're trying to do in the shell:
var school = db.schools.findOne({name: "high school"}) //assuming unique
school.departments.forEach(function(department) {
if(department.name === "math") {
department.courses.forEach(function(course) {
if(course.name === "algebra") {
course.lessons.forEach(function(lesson) {
if(lesson.name === "algebra 1a") {
lesson.students.push({name: "Jon", id: "43953"});
}
});
}
});
}
})
db.schools.save(school)
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