Understanding the Issue with MariaDB INSERT Statements in Node.js

As a developer, we’ve all been there at some point or another - staring at our code, scratching our heads, trying to figure out why things just aren’t working as expected. In this article, we’ll delve into a common issue that can occur when interacting with MariaDB databases using Node.js and explore how to resolve it.

The Problem: Understanding MariaDB Syntax

MariaDB is a popular open-source relational database management system (RDBMS) that is widely used for web applications, especially those built on Node.js. When working with MariaDB in Node.js, we often use the mariadb library to interact with the database.

In this specific case, our developer has encountered an issue when trying to insert data into a table called “achievements”. The error message they’re receiving is quite informative:

(conn=1194, no: 1136, SQLState: 21S01) Column count doesn't match value count at row 1

Let’s break down what this means.

MariaDB Syntax: Understanding the INSERT INTO Statement

In MariaDB, just like in other RDBMS systems, we use the INSERT INTO statement to add new data into a table. The basic syntax is as follows:

INSERT INTO table_name (column1, column2, ...) 
VALUES (value1, value2, ...);

Here, table_name is the name of the database table we want to insert data into, and column1, column2, etc. are the names of the columns within that table.

However, in our example, the developer has made a small mistake - they’re using value instead of VALUES. And, most importantly, they haven’t actually specified which columns they want to insert data into.

The Role of Column Count

In MariaDB (and other RDBMS systems), each column within a table must have a specific width. This is known as the “data type” for that column.

For example, if we create a table with an integer column called id, we can’t insert a string value into it. Similarly, if we try to insert data into multiple columns without specifying them in our INSERT statement, MariaDB will throw an error because the column count doesn’t match the number of values being inserted.

Resolving the Issue: Understanding the Correct Syntax

To resolve this issue, we need to modify our code so that it specifies the exact columns we want to insert data into. Here’s how we can do it:

const response = await global.conn.query(
  "INSERT INTO achievements (name, user_id, challenge_id, desc) 
   VALUES (?, ?, ?, ?);",
  Object.values(achievement)
);

Notice the addition of (name, user_id, challenge_id, desc) in our INSERT statement. This specifies that we want to insert data into these exact columns.

Also note the use of ? instead of actual values. In MariaDB (and other RDBMS systems), placeholders for parameter values are denoted by ?. These placeholders will be replaced with the actual values when executing the query.

Putting it All Together: Full Example Code

Here’s the complete example code that demonstrates how to insert data into a table using MariaDB:

const mariadb = require("mariadb");

(() => {
  setTimeout(async () => {
    console.log("connecting to db...");
    try {
      const pool = await mariadb.createPool({
        host: "localhost", //172.17.0.1
        user: "root",
        database: "gamifydb",
        port: "3306",
        password: "password"
      });
      const conn = await pool.getConnection();
      global.conn = conn;
      console.log("mariadb db connected");
    } catch (error) {
      throw error;
    }
  }, 1000);
})();

const achievement = {
  name: "lorem",
  user_id: "lorem",
  challenge_id:2,
  desc:"lorem"
};

exports.createAchievement = async achievement => {
  try {
    const response = await global.conn.query(
      "INSERT INTO achievements (name, user_id, challenge_id, desc) 
       VALUES (?, ?, ?, ?);",
      Object.values(achievement)
    );
    console.log(response);
    return response;
  } catch (error) {
    throw error;
  }
};

Conclusion

Resolving issues with MariaDB INSERT statements in Node.js requires a good understanding of the underlying syntax and how to specify columns correctly. By following the steps outlined above, we can ensure that our code is working as expected and insert data into tables successfully.

We hope this article has provided you with a deeper understanding of MariaDB and how to use it effectively in your Node.js applications. If you have any questions or need further clarification on any part of the process, feel free to ask!

Last modified on 2024-10-08