使用Nodejs找出SQL DB是否存在

const mysql = require('mysql');

const connection = mysql.createConnection({
  host: 'localhost',
  user: 'username',
  password: 'password',
  database: 'database_name'
});

connection.connect((err) => {
  if (err) {
    console.error('Error connecting to MySQL database:', err);
    return;
  }

  const query = `SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = 'your_database_name'`;
  connection.query(query, (error, results) => {
    if (error) {
      console.error('Error querying MySQL database:', error);
      return;
    }

    if (results.length > 0) {
      console.log('The database exists.');
    } else {
      console.log('The database does not exist.');
    }

    connection.end();
  });
});

const { Pool } = require('pg');

const pool = new Pool({
  user: 'username',
  host: 'localhost',
  password: 'password',
  database: 'database_name',
  port: 5432,
});

pool.connect((err, client, done) => {
  if (err) {
    console.error('Error connecting to PostgreSQL database:', err);
    return;
  }

  const query = `SELECT datname FROM pg_database WHERE datname = 'your_database_name'`;
  client.query(query, (error, result) => {
    if (error) {
      console.error('Error querying PostgreSQL database:', error);
      return;
    }

    if (result.rows.length > 0) {
      console.log('The database exists.');
    } else {
      console.log('The database does not exist.');
    }

    done();
    pool.end();
  });
});

const sql = require('mssql');

const config = {
  user: 'username',
  password: 'password',
  server: 'localhost',
  database: 'database_name',
};

sql.connect(config, (err) => {
  if (err) {
    console.error('Error connecting to SQL Server database:', err);
    return;
  }

  const query = `SELECT * FROM sys.databases WHERE name = 'your_database_name'`;
  new sql.Request().query(query, (error, result) => {
    if (error) {
      console.error('Error querying SQL Server database:', error);
      return;
    }

    if (result.recordset.length > 0) {
      console.log('The database exists.');
    } else {
      console.log('The database does not exist.');
    }

    sql.close();
  });
});