What is MongoDB Server Side Pagination?
MongoDB is a popular document-oriented NoSQL database that stores data in JSON-like documents with dynamic schema. When working with large datasets, it is essential to implement pagination to improve performance and reduce the amount of data transferred over the network. In this article, we will discuss how to do server-side pagination in MongoDB.
Server-side pagination is a technique that splits large datasets into smaller chunks to make them more manageable. Instead of retrieving all data at once, the server sends a subset of the data to the client on each request. In this way, the server can optimize the data retrieval process, and the client can display the data more efficiently.
To implement server-side pagination in MongoDB, we can use the limit() and skip() methods, which allow us to specify how many documents we want to retrieve and how many documents we want to skip, respectively.
Here is a step-by-step guide to implementing server-side pagination in MongoDB:
How can we define the page size?
The first step is to define the page size, which determines how many documents we want to retrieve on each request. We can set the page size to any value that makes sense for our application. Typically, the page size ranges from 10 to 100 documents per page.
How to calculate the number of pages?
To calculate the number of pages, we must divide the total number of documents by page size. We can use the count() method to count the total number of documents in the collection.
const pageSize = 10;
const totalCount = await db.collection('users').count();
const totalPages = Math.ceil(totalCount / pageSize);
How to retrieve data for a specific page
To retrieve data for a specific page, we need to use the limit() and skip() methods. The limit() method limits the number of documents to retrieve, and the skip() method skips a certain number of documents before starting to retrieve them.
const pageNumber = 1;
const users = await db.collection('users') .find({}) .limit(pageSize) .skip(
(pageNumber - 1) * pageSize
) .toArray();
In the example above, we retrieve the first page of users, which contains pageSize number of documents. We skip the documents on all the previous pages by multiplying the page number by the page size and subtracting 1.
How can we display the data?
After retrieving the data for a specific page, we can display it to the user. We can use any front-end framework or library to display the data, such as Angular, React, or Vue.
Implement pagination links
Finally, we can implement pagination links to allow users to navigate between pages. We can use the totalPages value calculated in step 2 to generate the links.
const paginationLinks = [];
for (
let i = 1;
i <= totalPages;
i ++
) { paginationLinks.push(
{ pageNumber: i, isActive : i === pageNumber }
);
}
In the example above, we generate an array of pagination links, where each link has a pageNumber property and an isActive property that indicates whether the link is for the current page.
Conclusion
Server-side pagination is an effective technique to handle large datasets in MongoDB. By using the limit() and skip() methods, we can retrieve a subset of the data on each request and optimize the data retrieval process. Moreover, by implementing pagination links, we can provide a better user experience and improve the performance of our application.