SQLite Node.js – Deleting Data

Summary: in this tutorial, you will learn how to delete data in the SQLite database from a Node.js application.

To delete data in the SQLite database from a Node.js application, you use the following steps:

1. Open a database connection.
2. Execute a DELETE statement.
3. Close the database connection.

For the demonstration, we will use the langs table in the sample.db database that we created in the previous tutorial.

Deleting data example

To delete data from a table, you use the DELETE statement as follows:

DELETE FROM table_name
WHERE column_name = value;Code language: JavaScript (javascript)

To execute the DELETE statement from a Node.js application, you call the run() method of the Database object as follows:

db.run(sql, params, function(err) {
  // 
});
Code language: JavaScript (javascript)

The run() method allows you to execute a DELETE statement with specified parameters and calls a callback function afterward.

If there was any error during the execution of DELETE statement, the err argument of the callback function will provide the details.

If the DELETE statement executed successfully, the this object of the callback function will contain the changes property that stores the number of rows deleted.

The following delete.js program illustrates how to delete a row from the langs table:

const sqlite3 = require('sqlite3').verbose();

// open a database connection
let db = new sqlite3.Database('./db/sample.db', (err) => {
  if (err) {
    console.error(err.message);
  }
});

let id = 1;
// delete a row based on id
db.run(`DELETE FROM langs WHERE rowid=?`, id, function(err) {
  if (err) {
    return console.error(err.message);
  }
  console.log(`Row(s) deleted ${this.changes}`);
});

// close the database connection
db.close((err) => {
  if (err) {
    return console.error(err.message);
  }
});
Code language: JavaScript (javascript)

Let’s test the update.js program.

>node delete.js
Row(s) deleted: 1Code language: JavaScript (javascript)

The output showed that one row had been deleted successfully.

In this tutorial, you have learned how to delete data in the SQLite database from a Node.js application.