I would choose [Sequelize][1] because of it&#39;s excellent documentation. It&#39;s just a honest opinion (I never really used MySQL with Node that much).


  [1]: http://sequelizejs.com/


May I suggest Node ORM?

https://github.com/dresende/node-orm2

There&#39;s documentation on the Readme, supports MySQL, PostgreSQL and SQLite.

MongoDB is available since version **2.1.x** (released in July 2013)

UPDATE: This package is no longer maintained, per the project&#39;s README. It instead recommends [bookshelf][1] and [sequelize][2]

  [1]: https://github.com/bookshelf/bookshelf
  [2]: https://github.com/sequelize/sequelize

First off, please note that I haven&#39;t used either of them (but have used Node.js).

Both libraries are documented quite well and have a
stable API. However, persistence.js seems to be [used in more projects](http://persistencejs.org/users). I don&#39;t know if all of them still use it, though.

The developer of sequelize sometimes blogs about it at [blog.depold.com][1]. When you&#39;d like to use primary keys as foreign keys, you&#39;ll need the patch that&#39;s described in [this blog post][2]. If you&#39;d like help for persistence.js there is a google group devoted to it.

From the examples I gather that sequelize is a bit more JavaScript-like (more sugar) than persistance.js but has support for fewer datastores (only MySQL, while persistance.js can even use in-browser stores).

I think that sequelize might be the way to go for you, as you only need MySQL support. However, if you need some convenient features (for instance search) or want to use a different database later on you&#39;d need to use persistence.js.


  [1]: http://blog.depold.com
  [2]: http://www.hiddentao.com/archives/2011/11/18/primary-key-foreign-key-improvements-to-sequelize-date-js-alternatives/

One major difference between Sequelize and Persistence.js is that the former supports a `STRING` datatype, i.e. `VARCHAR(255)`. I felt really uncomfortable making everything `TEXT`.

Where are the settings to show a `space`, `tab`, `paragraph`, `CRLF`, etc. (*extended*) characters? 

Show space, tab, CRLF characters in editor of Visual Studio

I find that when I position an element fixed, it doesn&#39;t matter if the parent is positioned relative or not, it will position fixed, relative to the window?

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-css --&gt;

    #wrapper {
      width: 300px;
      background: orange;
      margin: 0 auto;
      position: relative;
    }

    #feedback {
      position: fixed;
      right: 0;
      top: 120px;
    }

&lt;!-- language: lang-html --&gt;

    &lt;div id=&quot;wrapper&quot;&gt;
        ...
        &lt;a id=&quot;feedback&quot; href=&quot;#&quot;&gt;Feedback&lt;/a&gt;
    &lt;/div&gt;

&lt;!-- end snippet --&gt;

http://jsbin.com/ibesa3

Can I position an element fixed relative to parent?

I&#39;m rewriting a project to use Node.js. I&#39;d like to keep using MySQL as the DB (even though I don&#39;t mind rewriting the schema).
I&#39;m looking for a simple-to-use, reasonable-performance ORM, which supports caching, many-to-one and many-to-many relations.
From the MySQL ORMs I could find, [persistencejs](https://github.com/coresmart/persistencejs) and [sequelize](http://sequelizejs.com) seem the most mature. 
Do you have experience with either? What are the relevant pros and cons I should be aware of in my decision?

Which ORM should I use for Node.js and MySQL?

<p>I'm rewriting a project to use Node.js. I'd like to keep using MySQL as the DB (even though I don't mind rewriting the schema).
I'm looking for a simple-to-use, reasonable-performance ORM, which supports caching, many-to-one and many-to-many relations.
From the MySQL ORMs I could find, <a href="https://github.com/coresmart/persistencejs" target="_blank" rel="noopener noreferrer">persistencejs</a> and <a href="http://sequelizejs.com" target="_blank" rel="noopener noreferrer">sequelize</a> seem the most mature.
Do you have experience with either? What are the relevant pros and cons I should be aware of in my decision?</p>


I get a datetime field, that&#39;s currently in the query as:

    SELECT DATE_FORMAT(x.date_entered, &#39;%Y-%m-%d&#39;) AS date FROM x ORDER BY date ASC

What I want to do is to subtract 3 hours from that date (GMT issues), but I can&#39;t do it in PHP as PHP only knows the date part, not the time.

How to subtract hours from a datetime in MySQL?

I am using python MySQL API to connect to Mysql database from python program. I am facing a problem from few days. I am unable to insert records into the database and dont know whats the reason. Here is the way i connect and insert records into the database.

    db = MySQLdb.connect(&quot;localhost&quot;,&quot;root&quot;,&quot;padmaramulu&quot;,&quot;pdfsearch&quot; )
    cursor = db.cursor()
    #cursor.execute(&quot;&quot;&quot;CREATE TABLE IF NOT EXISTS documents (docid INT NOT NULL ,PRIMARY KEY(docid),docname CHAR(30)) engine=innodb&quot;&quot;&quot;)
    temp = &quot;hello&quot;;number = 2;
    cursor.execute( &#39;insert into documents(docid,docname) values(&quot;%d&quot;,&quot;%s&quot;)&#39; % (number,temp) )
    db.close()

Why is it so?


Python MySql Insert not working

    UPDATE AggregatedData SET datenum=&quot;734152.979166667&quot;, 
    Timestamp=&quot;2010-01-14 23:30:00.000&quot; WHERE datenum=&quot;734152.979166667&quot;;

It works if the `datenum` exists, but  I want to insert this data as a new row if the `datenum` does not exist. 
 

UPDATE

the datenum is unique but that&#39;s not the primary key

MySql Table Insert if not exist otherwise update

I need some help writing a MySQL query to show me rows from last month, but not the whole month, only up and until the same day, hour and minute as it is now(), but 1 month before.

So for example, if today is 5/19 at 5:25pm I need to select rows from midnight 12:00am 4/1 to 5:25pm of 4/19 (from the same year too of course). 

Thanks!

MySQL select all rows from last month until (now() - 1 month), for comparative purposes

This is not a full/correct MySQL query only pseudo-code:
   

    Select *
     from Notifications as n
     where n.date &gt; (CurrentDate-10 days)
     limit by 1
     FOR UPDATE

http://dev.mysql.com/doc/refman/5.0/en/select.html states:
If you use FOR UPDATE with a storage engine that uses page or row locks, rows examined by the query are write-locked until the end of the current transaction

Is here only the one record returned locked by MySQL or all records it has to scan to find the single record?


When using MySQL&#39;s FOR UPDATE locking, what is exactly locked?

I have a model `Coupon`, and a model `Photo` with a `ForeignKey` to it:

    class Photo(models.Model):
        coupon = models.ForeignKey(Coupon,
                                   related_name=&#39;description_photos&#39;)
        title = models.CharField(max_length=100)
        image = models.ImageField(upload_to=&#39;images&#39;)

I set up inlines in the admin so now I&#39;m able to add photos to a coupon from the admin.

I attempt to add one, and upload is successful, but then I get Django&#39;s debug page with this error:

    IntegrityError at /admin/coupon/coupon/321/
    (1452, &#39;Cannot add or update a child row: a foreign key constraint fails (`my_project`.`coupon_photo`, CONSTRAINT `coupon_id_refs_id_90d7f06` FOREIGN KEY (`coupon_id`) REFERENCES `coupon_coupon` (`id`))&#39;)

What is this and how can I solve this problem?

(If it matters, this is a MySQL database.)

**EDIT:** I tried it on an Sqlite3 database that has a slightly different dataset, and it worked, so perhaps there&#39;s loose data in my current DB? How can I find it and delete it?

Django &quot;Cannot add or update a child row: a foreign key constraint fails&quot;

I keep hearing about the Entity Framework fluent-api but I am struggling to find a good reference on this. What is it?

We use the entity framework and the modeling tool provided. Is that all that is? Or is it something different?

Similarly, if it&#39;s not too broad a question, what is POCO? I know it stands for Plain Old CLR Objects, but what does that mean to me as somebody who uses EF already with the designer model tool? If that question is too vague then please ignore it. I&#39;m just learning here and any information you are willing to provide is helpful.

What is Entity Framework fluent api?

I am using SQlAlchemy in my web project. What should I use - `scoped_session(sessionmaker())` or plain `sessionmaker()` - and why? Or should I use something else? 

    ## model.py
    from sqlalchemy import *
    from sqlalchemy.orm import *
    
    engine = create_engine(&#39;mysql://dbUser:dbPassword@dbServer:dbPort/dbName&#39;,
    pool_recycle=3600, echo=False)
    metadata = MetaData(engine)
    Session = scoped_session(sessionmaker())
    Session.configure(bind=engine)
    user = Table(&#39;user&#39;, metadata, autoload=True)

    class User(object):
	pass

    usermapper = mapper(User, user)

    ## some other python file called abc.py
    from models import *

    def getalluser():
       session = Session()	
       session.query(User).all()
       session.flush()
       session.close()

    ## onemore file defg.py
    from models import *

    def updateuser():
       session = Session()	
       session.query(User).filter(User.user_id == &#39;4&#39;).update({User.user_lname: &#39;villkoo&#39;})
       session.commit()
       session.flush()
       session.close()

I create a `session = Session()` object for each request and I close it. Am I doing the right thing or is there a better way to do it?



scoped_session(sessionmaker()) or plain sessionmaker() in sqlalchemy?

According to [the documentation](http://docs.sqlalchemy.org/en/latest/core/constraints.html#indexes) and the comments in the `sqlalchemy.Column` class, we should use the class `sqlalchemy.schema.Index` to specify an index that contains multiple columns.

However, the example shows how to do it by directly using the Table object like this:

    meta = MetaData()
    mytable = Table(&#39;mytable&#39;, meta,
        # an indexed column, with index &quot;ix_mytable_col1&quot;
        Column(&#39;col1&#39;, Integer, index=True),
    
        # a uniquely indexed column with index &quot;ix_mytable_col2&quot;
        Column(&#39;col2&#39;, Integer, index=True, unique=True),
    
        Column(&#39;col3&#39;, Integer),
        Column(&#39;col4&#39;, Integer),
    
        Column(&#39;col5&#39;, Integer),
        Column(&#39;col6&#39;, Integer),
        )
    
    # place an index on col3, col4
    Index(&#39;idx_col34&#39;, mytable.c.col3, mytable.c.col4)


How should we do it if we use the declarative ORM extension?


    class A(Base):
        __tablename__ = &#39;table_A&#39;
        id = Column(Integer, , primary_key=True)
        a = Column(String(32))
        b = Column(String(32))

I  would like an index on column &quot;a&quot; and &quot;b&quot;.

Multiple columns index when using the declarative ORM extension of sqlalchemy

It&#39;s possible to define enumerations in JPA using either

    @Enumerated(EnumType.ORDINAL)
or

    @Enumerated(EnumType.STRING)

I wonder what are advantages and disadvantages of those two definitions? 

I heard that ORDINAL performs better (is faster) than STRING with EclipseLink.  
Is that true?
  

JPA Enum ORDINAL vs STRING

So I&#39;m trying to make a very basic node.js server that with take in a request for a string, randomly select one from an array and return the selected string.  Unfortunately I&#39;m running into a few problems.

Here&#39;s the front end:

    function newGame()
    {
       guessCnt=0;
       guess=&quot;&quot;;
       server();
       displayHash();
       displayGuessStr();
       displayGuessCnt();
    }
     
    function server()
    {
       xmlhttp = new XMLHttpRequest();
	
       xmlhttp.open(&quot;GET&quot;,&quot;server.js&quot;, true);
       xmlhttp.send();
	
       string=xmlhttp.responseText;
    }

This should send the request to server.js:

    var http = require(&#39;http&#39;);

    var choices=[&quot;hello world&quot;, &quot;goodbye world&quot;];

    console.log(&quot;server initialized&quot;);

    http.createServer(function(request, response)
    {
        console.log(&quot;request recieved&quot;);
        var string = choices[Math.floor(Math.random()*choices.length)];
        console.log(&quot;string &#39;&quot; + string + &quot;&#39; chosen&quot;);
        response.on(string);
        console.log(&quot;string sent&quot;);
    }).listen(8001);

So clearly there are several things going wrong here:

   1. I get the feeling the way I am &quot;connecting&quot; these two files isn&#39;t correct both in the `xmlhttp.open` method and in using `response.on` to send the string back to the front end.

   2. I&#39;m a little confused with how I call this page on localhost.  The front end is named index.html and the sever posts to 8001.  What address should I be go to on localhost in order to access the initial html page after I have initialized server.js? Should I change it to `.listen(index.html)` or something like that?

   3. are there other obvious problems with how I am implementing this (using `.responsetext` etc.)

(sorry for the long multi-question post but the various tutorials and the node.js source all assume that the user already has an understanding of these things.)


Basic Ajax send/receive with node.js

I have a problem where I want to be able to get all the unique cities for a collection, and my code looks something like this:

    var mongoose = require(&quot;mongoose&quot;),
    Schema = mongoose.Schema;

    var PersonSchema = new Schema({
        name: String,
        born_in_city: String
    });
    var Person = mongoose.model(&#39;Person&#39;, PersonSchema);

In native MongoDb I could just do `db.person.distinct(&quot;born_in_city&quot;)`, but there doesn&#39;t seem to be anything equivalent for Mongoose. Is the only option to iterate over all of the documents myself to do this, or is there a better solution?

In an attempt to use the underlying `node-mongodb-native` as suggested by the answerer I attempted to do this:

    mongoose.connection.db.collections(function(err, collections){
      collections[0].distinct(&#39;born_in_city&#39;, function( err, results ){
        console.log( err, results );
      });
    });

However the `results` is empty and there&#39;s no error. I would also prefer to be able to fetch only the needed collection by name rather than have to filter what `collections` return if at all possible.

How do I query for distinct values in Mongoose?

If I need to call 3 http API in sequential order, what would be a better alternative to the following code:


    http.get({ host: &#39;www.example.com&#39;, path: &#39;/api_1.php&#39; }, function(res) { 
      res.on(&#39;data&#39;, function(d) { 
      
        http.get({ host: &#39;www.example.com&#39;, path: &#39;/api_2.php&#39; }, function(res) { 
          res.on(&#39;data&#39;, function(d) { 
          
            http.get({ host: &#39;www.example.com&#39;, path: &#39;/api_3.php&#39; }, function(res) { 
              res.on(&#39;data&#39;, function(d) { 
              
               
              });
            });
            }
          });
        });
        }
      });
    });
    }
    


Make Requests in Sequential Order Node.js

In my NodeJS `express` application I have `app.js` that has a few common routes. Then in a `wf.js` file I would like to define a few more routes. 

How can I get `app.js` to recognize other route handlers defined in `wf.js` file? 

A simple _require_ does not seem to work.

How to include route handlers in multiple files in Express?

I want to run a very simple HTTP server. Every GET request to `example.com` should get `index.html` served to it but as a regular HTML page (i.e., same experience as when you read normal web pages).

Using the code below, I can read the content of `index.html`. How do I serve `index.html` as a regular web page?

    var http = require(&#39;http&#39;);
    var fs = require(&#39;fs&#39;);
    var index = fs.readFileSync(&#39;index.html&#39;);
    
    http.createServer(function (req, res) {
      res.writeHead(200, {&#39;Content-Type&#39;: &#39;text/plain&#39;});
      res.end(index);
    }).listen(9615);


----------

One suggestion below is complicated and requires me to write a `get` line for each resource (CSS, JavaScript, images) file I want to use. 

How can I serve a single HTML page with some images, CSS and JavaScript?

Content Type	Original Author	Original Content on Stackoverflow
Question	Near Privman	View Question on Stackoverflow
Solution 1 - Mysql	alessioalex	View Answer on Stackoverflow
Solution 2 - Mysql	dresende	View Answer on Stackoverflow
Solution 3 - Mysql	hey_lu	View Answer on Stackoverflow
Solution 4 - Mysql	Josh Smith	View Answer on Stackoverflow

Which ORM should I use for Node.js and MySQL?

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

Solution 3 - Mysql

Solution 4 - Mysql

Can I position an element fixed relative to parent?

Show space, tab, CRLF characters in editor of Visual Studio

Attributions