Ubuntu : Level 1 : Post 4.1 : More about Shell Scripting in Linux Ubuntu

In this we will learn other things about shell-scripting Shortcuts in bash: history: Command that shows you previous commands that you have typed in this shell. Use ! to execute a command corresponding to a number. Ctrl-r: Searches for a command in history. When found, just press Enter to execute it. Ctrl-p: Go to the previous… Read More »

Ubuntu : Level 1 : Post 4 : Shell Scripting in Linux Ubuntu

There are various types of shell on unix platform through which we do shell scripting: Bourne shell (sh) Bourne Again shell (bash) Korn shell (ksh) C shell (csh) TOPS C shell (tcsh) To know in which is currently running on your system use the following command in terminal: echo $SHELL   To know all the… Read More »

MongoDB : Post 10 : Analysis specific query operators

There are 4 possible queries which are heavily used for analysis specific operations.Them being, $mod   $regex $text $where   $mod : $mod selects all documents from a collection where the value of the field divided by the divisor returns a specific remainder. Example 1 : The following query selects all documents from the collection… Read More »

MongoDB : Post 9.1 : Specific query operators : $type

$type : The operator is used when one is dealing with highly unstructured data ,where for the very same reason the data types are not predictable. This operator selects the documents where the value of the specified field is a part of the specified BSON type.Thus , it returns the documents where the BSON type… Read More »

MongoDB : Post 9 : Specific query operators : $exists

$exists : $exists operator , when true , $exists matches the documents that contain the field.It also includes the documents where the field value is ‘null’.When false, the query returns only the documents that do not contain the field.The example with various operators will give a better picture : Example 1 : The following query selects… Read More »

MongoDB : Post 8.3 : Logical query : $nor

$nor :  $nor performs a logical NOR opeartion on an array of one or more query expression and selects the documents that fail all the query expressions in the array.The example being : Example 1 : The query will return all documents whose field ‘age’ value is not equal to 25 and has the hobbies… Read More »

MongoDB : Post 8.2 : Logical query :$not

$not :  performs a logical NOT operation on the specified expression and selects document that do not match the expression. Example being :   Example 1 : The following query will select all documents from the collection ‘equality’ where the ‘age’ has value less than or equal 24 or the documents where ‘age’ field does… Read More »

MongoDB : Post 8.1 : Logical query : $and

$and :  performs a logical AND operation on an array of two or more data values and selects the document that satisfies all the expressions in the array. Should return a boolean true value in both the cases.The example states : Example 1 : The query selects all the documents from the collection ‘equality‘ where… Read More »

MongoDB : Post 8 : Logical query : $or

The logical queries in MongoDB basically revolve around 4 operators namely: $or $and $not $nor   $or : The $or operator performs a logical OR operation on an array of two or more data values that selects the documents that satisfy at least one of the expression data values.The examples would give a better idea:… Read More »

MongoDB : Post 7.5 : Comparing queries : $nin

$nin : The $nin operator selects all the documents where the field value is not specified in the array and if the field doesn’t exist. Example 1 : The following query gets all the documents from the collection ‘equality’ where hobbies are not equal to “Singing” or “Dancing”, in an array. Example 2 : Querying… Read More »

MongoDB : Post 7.4 : Comparing queries : $in

$in :  The $in operator selects the documents where the value of a field is equal to any value in the specified array. The $in operator is only used on fields having array as value.The examples will give a clearer picture: Example 1 : The following example selects all documents from the collection ‘equality’ where… Read More »

MongoDB : Post 7.3 : Comparing queries : $ne

$ne (not equal to ) : selects the documents where the value of the field is not equal to the specified value. This also includes the documents that do not contain the specified field.The following example will make it clear : Example 1 : The query will select all documents in the collection ‘equality’ where… Read More »

MongoDB : Post 7.2 : Comparing queries : $lt and $lte

$lt (also known as  less than) : $lt selects the documents from the ‘equality’ collection where the value of the field is less than the specified value. The following example will make it more clear: Example 1 : The following example will get all documents from the collection ‘equality’ where the field ‘age’ has value… Read More »

MongoDB : Post 7.1 : Comparing Queries : $gt and $gte

$gt (also works as greater than) :  selects those documents from the specified collection where the value of the field is greater than the specified value.  The following example would make it simple to understand. Example 1 : The following example will get all the documents from the ‘equality’ collection where the value of the… Read More »

Ubuntu : Level 1 : Post 1 : Introduction

Ubuntu is an easy to use Linux desktop. It is an acronym for “Humanity to Others”. This is one such Linux project that was established by Mark Shuttleworth, he named it “Debian”. Unlike other software it is does not create a barrier between the person who is using “Free” version by giving him less features… Read More »

Ubuntu : Level 1 : Post 2 : Basic commands in Ubuntu

Ubuntu, as we said earlier, is very user-friendly and have a better user interface. In Ubuntu there are some basic commands on which you need to get a hold. You can open the Terminal by pressing ‘Ctrl+Alt+T’. It is case sensitive so if be careful while typing the directories/file(s) names pwd: running this command on… Read More »

Excel : Level 1 : Post 10 : Excel Templates

An excel template is also a workbook, but it is used to make a new workbook. You will have properly formatted sheets, all you have to do is to insert your data values at designed places in the sheet. This is how a template works. Apart from a big list of available templates, you can… Read More »

MongoDB : Post 6.3 : Query planning in MongoDB

QUERY OPTIMIZER  The MongoDB query optimizer like any other query optimizer goes through the declared query and translates that into an executable program. It produces some code which can be later executed by the database system.This happens in a number of steps: Step 1 :-  The query is translated into some intermediate format. Step 2… Read More »