Mini Project: Task Manager Database — Part 2 (Query and Update Features)

Let's think about this for a moment

In a task manager application, some of the most common features are filtering by status, marking a task as complete, and finding overdue tasks. In this lesson, you'll get hands-on practice with query filters, comparison operators ($lt, $gt), update operators ($set, $currentDate), and updateOne/updateMany, using the data from Part 1. In a real app, this is exactly the kind of query the backend runs whenever a user filters, searches, or updates something, so this practice closely mirrors production code. Once you can write query and update logic correctly, you'll also have a solid foundation for the aggregation reports in Part 3.

Let's build it hands-on

First, try filtering with find() for tasks where status: "pending" and priority: "high". Next, find a task by its title and use updateOne() to change its status to "completed" — use the $set operator together with the $currentDate operator to automatically add an updatedAt timestamp field. Finally, use updateMany() to flag overdue: true on every task whose dueDate is earlier than today and whose status is still "pending" — use the comparison operator dueDate: { $lt: new Date() } in your filter.

You've successfully run a query that filters on both status and priority together
You've updated a task using updateOne() with the $set and $currentDate operators
You've flagged overdue tasks using updateMany() with the $lt operator

Code Example

javascript

// status = pending နှင့် priority = high ဖြစ်တဲ့ task များကို ရှာပါ
db.tasks.find({ status: "pending", priority: "high" })

// task တစ်ခုကို completed ပြောင်းပြီး updatedAt timestamp ထည့်ပါ
db.tasks.updateOne(
  { title: "Fix login bug" },
  {
    $set: { status: "completed" },
    $currentDate: { updatedAt: true }
  }
)

// dueDate ကျော်နေတဲ့ pending task အားလုံးကို overdue flag တင်ပါ
db.tasks.updateMany(
  { status: "pending", dueDate: { $lt: new Date() } },
  { $set: { overdue: true } }
)

// ပြောင်းလဲမှုများကို confirm လုပ်ပါ
db.tasks.find().pretty()

You should see

After each updateOne() and updateMany() run, matchedCount and modifiedCount are returned, and running find() again shows the status, updatedAt, and overdue fields have changed.

5-minute try-it

Find tasks with priority: "low" and use updateMany() to change all of their priority to "medium" at once — spend 5 minutes checking whether matchedCount and modifiedCount differ.

A quick word of caution

Before running updateMany() on production data, test your filter condition with find() first and carefully check exactly which documents it will touch — too broad a filter can end up updating far more documents than you intended.