CODEWITHSUNDEEP
javascriptnode.jssqlite
Tester232323
Tester232323

Reputation: 301

Node sqlite3 when to close db

I cannot figure out when to close a db in node-sqlite3, or really how to use the package in general. It seems if I run this, I get "no such table:rooms". Eventually after running it enough times, I might manage to make the table.

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

class RoomManager{
    constructor(options){

        this.db = this._createDb();
        this.table = "rooms";

        this._createTable();
        this.addRoom({
            name : 'test3'
        }).getRooms()
        this.deleteRoom({
            name : 'test3'
        }).getRooms();

        return this;
    }

    _createDb() {
        return new sqlite3.Database('chat');
    }

    _createTable(){
        this.db.run("CREATE TABLE IF NOT EXISTS " + this.table + " (name TEXT, size INT)");
        return this;
    }

    addRoom(options){
         this.db.run("INSERT INTO " + this.table + " (name, size) VALUES ($name, $size)", {
            $name : options.name,
            $size : options.size || 1000
        });
        return this;
    }

    getRooms(){
        this.db.all("SELECT rowid, name, size FROM " + this.table, function(err, rows) {
            rows.forEach(function (row) {
                console.log(row.rowid + ": " + row.name + " - " + row.size);
            });
        });
        return this;
    }

    getRoom(options){
        if(options.name){
            this.db.get("SELECT * FROM " + this.table + " WHERE name = $name", {
                $name : options.name
            }, function(err, row){
                return row;
            });
        }
    }

    deleteRoom(options){
        this.db.run("DELETE FROM " + this.table + " WHERE name = $name", {
            $name : options.name
        });
        return this;
    }
}

module.exports = RoomManager;

Upvotes: 1

Views: 2076

Answers (1)

Aikon Mogwai
Aikon Mogwai

Reputation: 5225

Your problem that Node is asynchronous. So, you must wait end of command by callback function. e.g. 

this.db.run(query, params, function(err) {
   if (err)
      return console.log(err);

   // do next query here
})

Sqlite module can control flow by db.serialize. Imho it's useless in common cases. Better use async module or promises for it.

Upvotes: 2

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