    SELECT DataId, COUNT(*) c FROM DataTab GROUP BY DataId HAVING c &gt; 1;

I have used it in my application. It is working based on your query

```
SELECT a.* 
FROM CENTERDETAILS a 
JOIN 
(SELECT IPADDR, MACID, COUNT(*) 
    FROM CENTERDETAILS  
    GROUP BY IPADDR, MACID 
    HAVING count(*) &gt; 1
) b ON a.IPADDR = b.IPADDR OR a.MACID = b.mac 
ORDER BY a.MACID
```

Does anyone know if there is any difference between doing `Task.Factory.StartNew` vs `new Task` followed by calling `Start` on the task. Looking at reflector there doesn&#39;t seem to be much difference. So perhaps the only difference is that `Task.Factory.StartNew`returns a task that is already started. Is this correct?

I know that `Task.Factory.StartNew`and `Task.Run` have different default options and `Task.Run` is the preferred option for .Net 4.5.

Task.Factory.StartNew vs new Task

I want my nginx make display all url&#39;s clean. 

  - http://www.mydomain.com/indexhtml.html as http://www.mydomain.com/indexhtml 
  - http://www.mydomain.com/indexphp.php as http://www.mydomain.com/indexphp

With some research I&#39;ve made the first case to work. It`s done by following configuration:

    location / {
        root   html;
        index  index.html index.htm index.php;
        try_files $uri.html $uri/ =404;	
    }

It works for indexhtml.html displaying as indexhtml, but nothing happens with .php. If I change $uri.html to $uri.php, it works neither for .html, neither .php. I`ve tried to put something similar in php location but without any success.

Any advices?

How to remove both .php and .html extensions from url using NGINX?

I have inserted some values in the table `DataTab`. &lt;br&gt;

    SomeId: Integer     =&gt; Autogenerated primary key.
    DataId: Guid
    DataNumber: Integer
    DataType: varchar

The above are the column&#39;s in my tables, I want to find, if the table contains Repeated `DataId` values.
It has been long time I had worked with databases. Now I can figure out simple queries. But I found this some what difficult.

I tried the following query, is this correct?

    SELECT * from (Select * from DataTab) AS X 
    where DataId= X.DataId AND SomeId!=X.SomeId

Find duplicate column value in sqlite

I have inserted some values in the table <code>DataTab</code>. 
<pre><code class="hljs language-vbnet">SomeId: Integer => Autogenerated primary key.
DataId: Guid
DataNumber: Integer
DataType: varchar
</code></pre>
The above are the column's in my tables, I want to find, if the table contains Repeated <code>DataId</code> values.
It has been long time I had worked with databases. Now I can figure out simple queries. But I found this some what difficult.
I tried the following query, is this correct?
<pre><code class="hljs language-vbnet">SELECT * from (Select * from DataTab) AS X 
where DataId= X.DataId AND SomeId!=X.SomeId
</code></pre>

There is a post about a Redis command to get all available keys, but I would like to do it with Python.

Any way to do this?

Get all keys in Redis database with python

Suppose I have a collection that contains the following documents:

	{ &quot;_id&quot;: 1, name: &quot;Apple&quot; }
	{ &quot;_id&quot;: 2, name: &quot;Banana&quot;, &quot;is_reported&quot;: null }
	{ &quot;_id&quot;: 3, name: &quot;Cherry&quot;, &quot;is_reported&quot;: false }
	{ &quot;_id&quot;: 4, name: &quot;Kiwi&quot;,   &quot;is_reported&quot;: true }

Is there a simpler query to select all documents where &quot;is_reported&quot; is in a falsy state; that is, either non-existent, null, or false?  That is, a query that selects Apple, Banana, and Cherry, but not Kiwi?

[According to the MongoDB FAQ](http://docs.mongodb.org/manual/faq/developers/#faq-developers-query-for-nulls), `{ &quot;is_reported&quot;: null }` will select documents where &quot;is_reported&quot; is either null or nonexistent, but it still doesn&#39;t select documents where &quot;is_reported&quot; is false.

Right now I have the following query, which works fine, but it just doesn&#39;t seem very elegant.  If there are multiple fields that I need to select on, it gets messy very fast.  Is there a better query that achieves the same end result?

	db.fruits.find({ $or: [ { &quot;is_reported&quot;: null }, { &quot;is_reported&quot;: false } ] })

Select MongoDB documents where a field either does not exist, is null, or is false?

Every socket of MySQL Database will have defaults connections as 100 but I am looking for any way to increase the number of possible connections &gt; 100 to a socket connection of MySQL Database.


How to increase MySQL connections(max_connections)?

I am running PostgreSQL 9.3.1. I have `test` database and `backup` user which is used to backup the database. I have no problems with granting privileges to all current tables, but I have to grant privileges each time the new table is added to schema.

    createdb test

    psql test
    test=# create table foo();
    CREATE TABLE
    test=# grant all on all tables in schema public to backup;
    GRANT
    test=# create table bar();
    CREATE TABLE

    psql -U backup test
    test=&gt; select * from foo;
    test=&gt; select * from bar;
    ERROR:  permission denied for relation bar

Is it possible to grant access to tables which will be created in future without making user owner of the table?

Grant privileges on future tables in PostgreSQL?

When looking at tutorials there is often a delineation between a schema and a model, particularly when dealing with mongoose/mongodb. 
This makes porting over to postgresql somewhat confusing, as &#39;models&#39; don&#39;t seem to exist under that system. What is the difference the two approaches?

For example, what would be a postgres/sql ORM equivalent of this line? 

(mongoose and express.js):

    var userSchema = schema.define(&#39;local&#39;, {
        username:		String,
        password:		String,
    });

    module.exports = mongoose.model(&#39;User&#39;, userSchema);



Mongoose: Schema vs Model?

I&#39;m integrating **Google Analytics SDK 3.0** in my project. But I am getting **linker errors** when try to build my project.

As mentioned in the [documentation](https://developers.google.com/analytics/devguides/collection/ios/v3/#headers), I have linked following libraries in my project,

+ _libGoogleAnalyticsServices.a_
+ _AdSupport.framework_
+ _CoreData.framework_
+ _SystemConfiguration.framework_
+ _libz.dylib_

Even then, I get following errors on building the project,

    d: warning: directory not found for option &#39;-L&quot;/Users/....NameProject/Libraries/Google Analytics&quot;&#39;
    &quot;_sqlite3_bind_blob&quot;, referenced from:
      -[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
    &quot;_sqlite3_bind_int&quot;, referenced from:
      -[TAGDataLayerPersistentStoreImpl deleteEntries:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
    &quot;_sqlite3_bind_int64&quot;, referenced from:
      -[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
      -[TAGDataLayerPersistentStoreImpl peekEntryIds:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)

    ....

What is causing these errors? Am I missing anything? 

Appreciate your help.

----------


**SOLUTION:**

I solved it by linking my project with `libsqlite3.0` library. The Google analytics documentation missed out mentioning to link this library. Hope this helps.



Google Analytics SDK 3.0 _sqlite3 linker errors in iOS

I was reading through StackOverflow about this question and I still haven&#39;t found a solution. I notice that sometimes, my app throws this error:

       java.lang.IllegalStateException: Cannot perform this operation because the connection pool has been closed.
            at android.database.sqlite.SQLiteConnectionPool.throwIfClosedLocked(SQLiteConnectionPool.java:962)
            at android.database.sqlite.SQLiteConnectionPool.waitForConnection(SQLiteConnectionPool.java:599)
            at android.database.sqlite.SQLiteConnectionPool.acquireConnection(SQLiteConnectionPool.java:348)
            at android.database.sqlite.SQLiteSession.acquireConnection(SQLiteSession.java:894)
            ...

I have a file called `DatabaseHelper.java` using this approach to get an instance of it:

    public static DatabaseHelper getInstance(Context context) {
        if (mInstance == null) {
            mInstance = new DatabaseHelper(context.getApplicationContext());
        }
        return mInstance;
    }

Then I have methods like this one (that it crashed in the line `cursor.moveToFirst()` with that error). It almost never crashes, but sometimes it does.

    public Profile getProfile(long id) {
        SQLiteDatabase db = this.getReadableDatabase();

        String selectQuery = &quot;SELECT * FROM &quot; + TABLE_PROFILES + &quot; WHERE &quot; + KEY_PROFILES_ID + &quot; = &quot; + id;
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        Profile profile = new Profile();
        if (cursor.moveToFirst()) {
            doWhatEver();
        }
        cursor.close();
        db.close();

        return profile;
    }

So that&#39;s it, in all the methods I use: 

    SQLiteDatabase db = this.getReadableDatabase(); (or Writable)

And then I close the cursor and the db. In this case, the error got throw in the line:

    cursor.moveToFirst();

I do not see why the error says the db is closed if I am calling `this.getReadableDatabase()` before. Please support! Thank you :)

Android: Cannot perform this operation because the connection pool has been closed

I&#39;m looking for a way to access an SQLite database in my app with Swift code.

I know that I can use an SQLite Wrapper in Objective C and use the bridging header, but I&#39;d rather be able to do this project entirely in Swift. Is there a way to do this, if so, can someone point me to a reference that shows how to submit a query, retrieve rows, etc?

Accessing an SQLite Database in Swift

Typically, the sqlite store file for core data apps is located in 

&gt; Library&gt;Application Support&gt;iPhone Simulator&gt;7.1(or whichever version you are using)&gt;Applications&gt;(Whichever folder contains your app)&gt;Documents 

folder, but I can&#39;t find it in IOS 8.  I would assume they would just add an 8.0 folder inside the iPhone Simulator folder, but it&#39;s not there.  Has anybody been able to locate it?



Sqlite File Location Core Data

I am using SQLite as an application file format (see [here](http://www.sqlite.org/appfileformat.html) for why you would want to do this) for my PySide-based desktop application. That is, when a user uses my app, their data is saved in a single database file on their machine. I am using the SQLAlchemy ORM to communicate with the databases.

As I release new versions of the application, I may modify the database schema. I don&#39;t want users to have to throw away their data every time I change the schema, so I need to migrate their databases to the newest format. Also, I create temporary databases a lot to save subsets of the data for use with some external processes. I want to create these databases with alembic so they are tagged with the proper version.

I have a few questions:

* Is there a way to call alembic from inside my Python code? I think it&#39;s weird to have to use `Popen` to a pure Python module, but the docs just use alembic from the command line. Mainly, I need to change the database location to wherever the user&#39;s database is located. 

* If that&#39;s not possible, can I specify a new database location from the command line without editing the .ini file? This would make calling alembic through `Popen` not a big deal.

* I see that alembic keeps its version information under a simple table called `alembic_version`, with one column called `version_num` and a single row specifying the version. Can I add an `alembic_version` table to my schema and populate it with the latest version when I create new databases so there is no overhead? Is that even a good idea; should I just use alembic to create all databases?

I have alembic working great for the single database I use to develop with in my project&#39;s directory. I want to use alembic to conveniently migrate and create databases in arbitrary locations, preferably through some sort of Python API, and not the command line. This application is also frozen with cx_Freeze, in case that makes a difference.

Thanks!

Content Type	Original Author	Original Content on Stackoverflow
Question	51k	View Question on Stackoverflow
Solution 1 - Database	Jwalin Shah	View Answer on Stackoverflow
Solution 2 - Database	Ashok Kumar J	View Answer on Stackoverflow

Find duplicate column value in sqlite

Database Problem Overview

Database Solutions

Solution 1 - Database

Solution 2 - Database

How to remove both .php and .html extensions from url using NGINX?

Task.Factory.StartNew vs new Task

Attributions