Getting Started...
<ol>
<li>A document is the basic unit of data for MongoDB = Row in RDBMS
</li>
<li>Similarly, a collection can be thought of as a table with a dynamic schema.
</li>
<li>A single instance of MongoDB can host multiple independent databases, each of
which can have its own collections.
</li>
<li>Every document has a special key, "_id", = Primary Key
</li>
<li>MongoDB comes with a simple but powerful JavaScript shell.
</li>
<li>Document: an ordered set of keys with associated values. = Map or Dictionary
<pre><code>key: value 
</code></pre>Ex: {"greeting" : "Hello, world!"}
</li>
<li>IMP.
The keys in a document are strings. 
 Any UTF-8 character is allowed in a key, with a few notable exceptions:
</li>
</ol>
• Keys must not contain the character \0 (the null character). This character is used
to signify the end of a key.
• The . and $ characters have some special properties and should be used only in
certain circumstances. In general, they should be considered reserved, and drivers will complain if they are used inappropriately.
<ol>
<li>MongoDB is type-sensitive and case-sensitive. For example, these documents are
distinct:</li>
</ol>
{"foo" : 3} // string:num
{"foo" : "3"} //string:string
as are as these:
{"foo" : 3}
{"Foo" : 3}
<ol>
<li>MongoDB cannot contain duplicate keys.
</li>
<li>A collection is a group of documents.
</li>
</ol>

Getting Started...

1.  A document is the basic unit of data for MongoDB = Row in RDBMS

2. Similarly, a collection can be thought of as a table with a dynamic schema.

3. A single instance of MongoDB can host multiple independent databases, each of
   which can have its own collections.

4. Every document has a special key, "_id", = Primary Key

5. MongoDB comes with a simple but powerful JavaScript shell.

6. Document: an ordered set of keys with associated values. = Map or Dictionary
       key: value   
Ex: {"greeting" : "Hello, world!"}

7. IMP.
   The keys in a document are strings. 
    Any UTF-8 character is allowed in a key, with a few notable exceptions:

• Keys must not contain the character \0 (the null character). This character is used
to signify the end of a key.

• The . and $ characters have some special properties and should be used only in
certain circumstances. In general, they should be considered reserved, and drivers will complain if they are used inappropriately.

8. MongoDB is type-sensitive and case-sensitive. For example, these documents are
distinct:

{"foo" : 3} // string:num
{"foo" : "3"} //string:string

as are as these:

{"foo" : 3}
{"Foo" : 3}

9. MongoDB cannot contain duplicate keys.

10. A collection is a group of documents.

Basics: MongoDB