I want to have a simple fetch routes in my node.js but my problem is I dont know how to access the other table in mysql
router.get('/fetch' , async (req,res)=>{
const allData= await ("The problem is here").findAll({})
res.json(allData)
})
I don't know what Model should I put there. I'm using sequelize btw
and here is the list of all my table in mysql
and this is the model available in my node.js
i'm calling a stored procedure mysql using xdev nodejs driver. The stored procedure returns multiple resultset. When trying nextresultset, i'm getting only the non-empty resultset. So this messes with the resultant data index.
As far as I can understand, the problem is that nextResult() returns false when there are no items in the following result set.
This is an issue in a way that it breaks the following iterator pattern
const res = await session.sql('call proc_with_multiple_and_some_empty_result_sets()').execute()
do {
// do something
} while (res.nextResult())
and does not allow to easily consume the entire result set.
There are workarounds for this, such as using the toArray() method and iterate over the plain data:
res.toArray().forEach(item => {
// do something
})
However, this is a bug, and maybe you can submit a report on https://bugs.mysql.com/ under the Connector for Node.js category.
Disclaimer: I'm the lead dev of the MySQL X DevAPI Connector for Node.js
I am very new to nodejs and trying to create a registration API using nodejs, I search for it and got some code but the problem is developer is using MongoDB but I am using MYSQL. So my question is how to create a schema in MYSQL using nodejs, I got the code where developer created the schema in MongoDB.
Here is the code:
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const userSchema = new Schema({
email: String,
password: String,
});
module.exports = mongoose.model('user', userSchema, 'users');
Also Why we need schema in the first place can't I just create table in my database manually and Insert data using Insert Query.
Thanks.
You don´t need a specific schema if you are using mySQL. The database itself has a schema and won´t give you the chance to store malformed data if configured correctly. Mongoose provides a schema for mongoDB, because mongoDB is schema-less. You can store any kind of data and you won´t get an error back if malformed data was stored.
But of course if you are using TypeScript, you can build an interface or a class and validate data before storing without the use of any kind of third-party package
I would like to complete the following code using Entity Framework in .Net Core to query a JSON object from my API where my API is linked to MS SQL Server 2016. I don't want to take in the entire JSON and query from my backend, I want SQL to handle the querying using the MS JSON Functions and return only the queried information.
Something along the lines of:
var queryList = _context.myTable.Select(r => JSON_QUERY(r.myJsonColumn, '$.info')).ToList();
and
var valueList = _context.myTable.Select(r => JSON_VALUE(r.myJsonColumn, '$.info')).ToList();
I would like to do this without using a string inside the select statement and without creating my own function.
Overall I want a library where I can use JSON_VALUE, JSON_QUERY, ISJSON and JSON_MODIFY with my entity framework and linq.
is there any easy way to change the database from mysql to mongoDB ?
or better any one suggest me good tutorial do it
is there any easy way to change the database from mysql to mongoDB ?
Method #1: export from MySQL in a CSV format and then use the mongoimport tool. However, this does not always work well in terms of handling dates of binary data.
Method #2: script the transfer in your language of choice. Basically you write a program that reads everything from MySQL one element at a time and then inserts it into MongoDB.
Method #2 is better than #1, but it is still not adequate.
MongoDB uses collections instead of tables. MongoDB does not support joins. In every database I've seen, this means that your data structure in MongoDB is different from the structure in MySQL.
Because of this, there is no "universal tool" for porting SQL to MongoDB. Your data will need to be transformed before it reaches MongoDB.
If you're using Ruby, you can also try: Mongify
It's a super simple way to transform your data from a RDBS to MongoDB without losing anything.
Mongify will read your mysql database, build a translation file for you and all you have to do is map how you want your data transformed.
It supports:
Auto updating IDs (to BSON ObjectID)
Updating referencing IDs
Type Casting values
Embedding tables into other documents
Before save filters (to allow changes to the data manually)
and much much more...
Read more about it at: http://mongify.com/getting_started.html
There is also a short 5 min video on the homepage that shows you how easy it is.
Here's what I did it with Node.js for this purpose:
var mysql = require('mysql');
var MongoClient = require('mongodb').MongoClient;
function getMysqlTables(mysqlConnection, callback) {
mysqlConnection.query("show full tables where Table_Type = 'BASE TABLE';", function(error, results, fields) {
if (error) {
callback(error);
} else {
var tables = [];
results.forEach(function (row) {
for (var key in row) {
if (row.hasOwnProperty(key)) {
if(key.startsWith('Tables_in')) {
tables.push(row[key]);
}
}
}
});
callback(null, tables);
}
});
}
function tableToCollection(mysqlConnection, tableName, mongoCollection, callback) {
var sql = 'SELECT * FROM ' + tableName + ';';
mysqlConnection.query(sql, function (error, results, fields) {
if (error) {
callback(error);
} else {
if (results.length > 0) {
mongoCollection.insertMany(results, {}, function (error) {
if (error) {
callback(error);
} else {
callback(null);
}
});
} else {
callback(null);
}
}
});
}
MongoClient.connect("mongodb://localhost:27017/importedDb", function (error, db) {
if (error) throw error;
var MysqlCon = mysql.createConnection({
host: 'localhost',
user: 'root',
password: 'root',
port: 8889,
database: 'dbToExport'
});
MysqlCon.connect();
var jobs = 0;
getMysqlTables(MysqlCon, function(error, tables) {
tables.forEach(function(table) {
var collection = db.collection(table);
++jobs;
tableToCollection(MysqlCon, table, collection, function(error) {
if (error) throw error;
--jobs;
});
})
});
// Waiting for all jobs to complete before closing databases connections.
var interval = setInterval(function() {
if(jobs<=0) {
clearInterval(interval);
console.log('done!');
db.close();
MysqlCon.end();
}
}, 300);
});
MongoVUE's free version can do this automatically for you.
It can connect to both databases and perform the import
I think one of the easiest ways is to export the MySQL database to JSON and then use mongorestore to import it to a MongoDB database.
Step 1: Export the MySQL database to JSON
Load the mysql dump file into a MySQL database if necessary
Open MySQL Workbench and connect to the MySQL database
Go to the Schema viewer > Select database > Tables > right-click on the name of the table to export
Select 'Table Data Export Wizard'
Set the file format to .json and type in a filename such as tablename.json
Note: All tables will need to be exported individually
Step 2: Import the JSON files to a MongoDB using the mongorestore command
The mongorestore command should be run from the server command line (not the mongo shell)
Note that you may need to provide the authentication details as well as the --jsonArray option, see the mongorestore docs for more information
mongoimport -d dbname -u ${MONGO_USERNAME} -p ${MONGO_PASSWORD} --authenticationDatabase admin -c collectionname --jsonArray --file tablename.json
Note: This method will not work if the original MySQL database has BLOBs/binary data.
I am kind of partial to TalendOpenStudio for those kind of migration jobs. It is an eclipse based solution to create data migration "scripts" in a visual way. I do not like visual programming, but this is a problem domain I make an exception.
Adrien Mogenet has create a MongoDBConnection plugin for mongodb.
It is probably overkill for a "simple" migration but ut is a cool tool.
Mind however, that the suggestion of Nix will probably save you time if it is a one-of migration.
You can use QCubed (http://qcu.be) framework for that. The procedure would be something like this:
Install QCubed (http://www.thetrozone.com/qcubed-installation)
Do the codegen on your database. (http://www.thetrozone.com/php-code-generation-qcubed-eliminating-sql-hassle)
Take your database offline from the rest of the world so that only one operation runs at a time.
Now write a script which will read all rows from all tables of the database and use the getJson on all objects to get the json. You can then use the data to convert to array and push it into the mongoDB!
If anyone's still looking for a solution, i found that the easiest way is to write a PHP script to connect to your SQL DB, retrieve the information you want using the usual Select statement, transform the information into JSON using the PHP JSON Encode functions and simply output your results to file or directly to MongoDB. It's actually pretty simple and straight forward, the only thing to do is to double check your output against a Json validator, you may have to use functions such as explode to replace certain characters and symbols to make it valid. I have done this before however i currently do not have the script at hand but from what i can remember it was literally half a page of code.
Oh also remember Mongo is a document store so some data mapping is required to get it to be acceptable with mongo.
For those coming to this with the same problem, you can check out this Github project. This is an ongoing development that will help you migrate data from MySQL database to MongoDB by simply running a simple command.
It will generate MongoDB Schemas in TypeScript so you can use them later in your project. Each MySQL table will be a MongoDB collection, and datatypes will be efficiently converted to their MongoDB compatibles.
The documentation for the same can be found in the project's README.md. Feel free to come in and contribute. Would like to help if need be.
If you are looking for a tool to do it for you, good luck.
My suggestion is to just pick your language of choice, and read from one and write to another.
If I could quote Matt Briggs (it solved my roblem one time):
The driver way is by FAR the most straight forward. The import/export tools are fantastic, but only if you are using them as a pair. You are in for a wild ride if your table includes dates and you try to export from the db and import into mongo.
You are lucky too, being in c#. We are using ruby, and have a 32million row table we migrated to mongo. Our ending solution was to craft an insane sql statement in postgres that output json (including some pretty kludgy things to get dates going properly) and piped the output of that query on the command line into mongoimport. It took an incredibly frustrating day to write, and is not the sort of thing that can ever really be changed.
So if you can get away with it, use ado.net with the mongo driver. If not, I wish you well :-)
(note that this is coming from a total mongo fanboi)
MySQL is very similar to other SQL databases, so I send You to the topić:
Convert SQL table to mongoDB document
You can use the following project.It requires solr like configuration file to be written.Its very simple and straight forward.
http://code.google.com/p/sql-to-mongo-importer/
Try this:
Automated conversion of MySQL dump to Mongo updates using simple r2n mappings.
https://github.com/virtimus/mysql2mongo