What is an MDF file? [closed]

SQL Server databases use two files – an MDF file, known as the primary database file, which contains the schema and data, and a LDF file, which contains the logs. See wikipedia. A database may also use secondary database file, which normally uses a .ndf extension. As John S. indicates, these file extensions are purely convention … Read more

What are the differences between a HashMap and a Hashtable in Java?

There are several differences between HashMap and Hashtable in Java: Hashtable is synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones. Hashtable does not allow null keys or values. HashMap allows one null key and any number of null values. One of HashMap’s subclasses is LinkedHashMap, so in the event that you’d want predictable iteration order (which is insertion order by default), you … Read more

How do I force git pull to overwrite everything on every pull?

Really the ideal way to do this is to not use pull at all, but instead fetch and reset: (Altering master to whatever branch you want to be following.) pull is designed around merging changes together in some way, whereas reset is designed around simply making your local copy match a specific commit. You may want to consider slightly different options to clean depending on your system’s … Read more

‘App not Installed’ Error on Android

Primarily for older phones I only encountered the App not installed error when trying to install an apk on my phone which runs on 4.4.2 aka KitKat, but my friend did not encounter this error on his phone which runs on 6+. I tried the other solutions such as removing the old/debug version of the app because … Read more

How to deal with SettingWithCopyWarning in Pandas

The SettingWithCopyWarning was created to flag potentially confusing “chained” assignments, such as the following, which does not always work as expected, particularly when the first selection returns a copy. [see GH5390 and GH5597 for background discussion.] The warning offers a suggestion to rewrite as follows: However, this doesn’t fit your usage, which is equivalent to: While it’s clear that you don’t care … Read more

Emulator: ERROR: x86 emulation currently requires hardware acceleration

As per this response, the complete steps are: 1) Open SDK Manager (In Android Studio, go to Tools > Android > SDK Manager) and Download Intel x86 Emulator Accelerator (HAXM installer) if you haven’t. 2) Now go to your SDK directory C:\users\%USERNAME%\AppData\Local\Android\sdk\extras\intel\Hardware_Accelerated_Execution_Manager\ and run the file named intelhaxm-android.exe. In case you get an error like “Intel virtualization technology (vt,vt-x) … Read more

Docker: How to delete all local Docker images

For Unix To delete all containers including its volumes use, To delete all the images, Remember, you should remove all the containers before removing all the images from which those containers were created. For Windows In case you are working on Windows (Powershell), Based on the comment from CodeSix, one liner for Windows Powershell, For … Read more

Differences between git pull origin master & git pull origin/master

git pull origin master will pull changes from the origin remote, master branch and merge them to the local checked-out branch. git pull origin/master will pull changes from the locally stored branch origin/master and merge that to the local checked-out branch. The origin/master branch is essentially a “cached copy” of what was last pulled from origin, which is why it’s called a remote branch in git … Read more