Lsokolowski1: /* CRUD */

2023-09-13T20:29:02Z

CRUD

← Older revision		Revision as of 20:29, 13 September 2023
Line 124:		Line 124:
	''' Delete '''		''' Delete '''
	<syntaxhighlight lang="JavaScript">		<syntaxhighlight lang="JavaScript">
	db.people.remove({"Name" : "Sean Connery"})		db.people.remove({"Name" : "Sean Connery"}) // .remove() is depricated now, use .deleteOne() instead
	db.people.remove({})		db.people.remove({})
	db.people.findOne()		db.people.findOne()

Lsokolowski1: /* CRUD */

2023-09-13T20:22:56Z

CRUD

← Older revision		Revision as of 20:22, 13 September 2023
Line 105:		Line 105:
	use NobleProg		use NobleProg
	person = {"Name" : "Sean Connery", "Nationality" : "Great Britain"}		person = {"Name" : "Sean Connery", "Nationality" : "Great Britain"}
	db.people.insert(person)		db.people.insert(person) // .insert() is depricated now, use .insertOne() instead
	</syntaxhighlight>		</syntaxhighlight>

Line 118:		Line 118:
	<syntaxhighlight lang="JavaScript">		<syntaxhighlight lang="JavaScript">
	personUp = {"Occupation" : "Actor"}		personUp = {"Occupation" : "Actor"}
	db.people.update({"Name" : "Sean Connery"}, {$set: personUp})		db.people.update({"Name" : "Sean Connery"}, {$set: personUp}) // .update() is depricated now, use .updateOne() instead
	db.people.findOne()		db.people.findOne()
	</syntaxhighlight>		</syntaxhighlight>

Lsokolowski1: /* CRUD */

2023-09-13T20:20:54Z

CRUD

← Older revision		Revision as of 20:20, 13 September 2023
Line 112:		Line 112:
	db.people.find()		db.people.find()
	db.people.findOne()		db.people.findOne()
	db.people.find().pretty()		db.people.find().pretty() // .pretty() is the default now, so can be omitted
	</syntaxhighlight>		</syntaxhighlight>

Lsokolowski1: /* CRUD */

2023-09-13T20:19:06Z

CRUD

← Older revision		Revision as of 20:19, 13 September 2023
Line 117:		Line 117:
	''' Update '''		''' Update '''
	<syntaxhighlight lang="JavaScript">		<syntaxhighlight lang="JavaScript">
	~~person.~~Occupation = "Actor"		personUp = {"Occupation" : "Actor"}
	db.people.update({"Name" : "Sean Connery"}, ~~person~~)		db.people.update({"Name" : "Sean Connery"}, {$set: personUp})
	db.people.findOne()		db.people.findOne()
	</syntaxhighlight>		</syntaxhighlight>

Kbaran: /* MongoDB Shell */

2019-03-12T07:24:35Z

MongoDB Shell

New page

[[Category:MongoDB]]

== Introduction ==
* MongoDB is a fast document-oriented database
* replaces the concept of a "row" with a more flexible model - the "document"
* convenient data storage for modern object-oriented languages
* no predefined schemas
* no transactions
* no SQL
* supports indexes
* easy to scale out horizontally
 

=== Getting Started ===
* document is a basic unit of data (like row in RDBMS)
* collection = table
* multiple databases in single instance
* _id in every document, unique within collection
* JavaScript shell for administration and data manipulation
 

=== Documents ===
* document is an ordered set of keys with associated values
* representation of a document varies by programming language (map; hash - Perl, Ruby; dictionary - Python)
* objects in JavaScript {key:value}
* example {"company" : "NobleProg", "training" : "MongoDB for Developers"}
* key is a string, any UTF-8 is allowed (except \0 . $)
* type-sensitive {"age" : 3}, {"age" : "3"}
* case-sensitive {"age" : 3}, {"Age" : 3}
* documents cannot contain duplicated keys
* key/value pairs are ordered {"x" : 1, "y" : 1} != {"y" : 1, "x" : 1}
** order does not usually matter, MongoDB can reorder keys
 
<syntaxhighlight lang="JavaScript">
{
"_id" : ObjectId("545a414c7907b2a255b156c5"),
"Name" : "Sean Connery",
"Nationality" : "Great Britain",
"BirthDate" : ISODate("1930-08-25T00:00:00Z"),
"BirthYear" : 1930,
"Occupation" : [
"Actor",
"Director",
"Producer"
],
"Movie" : [
{
"_id" : ObjectId("545a5f167907b2a255b156c7"),
"Title" : "Dr. No"
},
{
"_id" : ObjectId("545a5f317907b2a255b156c8"),
"Title" : "From Russia with Love"
},
{
"_id" : ObjectId("545a5ed67907b2a255b156c6"),
"Title" : "Never Say Never Again"
}
],
"BirthPlace" : {
"Country" : "United Kingdom, Scotland",
"City" : "Edinburgh"
}
}
</syntaxhighlight>
 

=== Collections ===
* a group of documents
* dynamic schemas
** {"company" : "NobleProg"}
** {"age" : 5}
* why should we use more than one collection?
** nightmare for developers
** much faster to get a list of collections than extracting document types from collections
** grouping documents of the same kind
** indexes
* collection name is a string, any UTF-8 is allowed except:
** empty string, start with "system." prefix, contain \0 character, $ character
* subcollections separated by the . character
** example GridFS (fs.files, fs.chunks)
 

=== Databases ===
* database is a group of collections
* one database = one application
* separated databases for different applications, users
* database name is a alphanumeric string, case sensitive, max 64 bytes, empty string is not allowed
* database name will end up as file on filesystem (this explains restrictions)
* special databases: admin (root database), local (never replicated), config (when sharding)
* namespace is a concatenation of database and collection name (fully qualified collection name)
** max 121 bytes, shold be less than 100
 

=== Getting and Starting MongoDB ===
# Installation on Windows
#* http://docs.mongodb.org/manual/tutorial/install-mongodb-on-windows/
# Installation on Ubuntu
#* http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/
 

=== CRUD ===
''' Create '''
<syntaxhighlight lang="JavaScript">
use NobleProg
person = {"Name" : "Sean Connery", "Nationality" : "Great Britain"}
db.people.insert(person)
</syntaxhighlight>

''' Read '''
<syntaxhighlight lang="JavaScript">
db.people.find()
db.people.findOne()
db.people.find().pretty()
</syntaxhighlight>

''' Update '''
<syntaxhighlight lang="JavaScript">
person.Occupation = "Actor"
db.people.update({"Name" : "Sean Connery"}, person)
db.people.findOne()
</syntaxhighlight>

''' Delete '''
<syntaxhighlight lang="JavaScript">
db.people.remove({"Name" : "Sean Connery"})
db.people.remove({})
db.people.findOne()
</syntaxhighlight>
 

=== Data Types ===
* JSON-like documents
** 6 data types: null, boolean, numeric, string, array, object
* MongoDB adds support for other datatypes
** null {"x" : null}
** boolean {"x" : true}
** number (by default 64-bit floating point numbers) {"x" : 1.4142}
*** 4-byte integers {"x" : NumberInt(141)}
*** 8-byte integers {"x" : LongInt(141)}
** string (any UTF-8 character) {"x" : "NobleProg"}
** date (stored as milliseconds from Linux epoch) {"x" : new Date()}
** regular expressions (in queries) {"x" : /bob/i}
** array {"x" : [1.4142, true, "training"]}
** embedded documents {"x" : {"y" : 100}}
** ObjectId {"x" : ObjectId("54597591bb107f6ef5989771")}
** binary data (for non-UTF-8 strings)
** code {"x" : function() {/*...*/}}
 

=== _id and ObjectId ===
* every document in MongoDB must have _id
* can be any type but it defaults to ObjectId
* unique values in a single collection
* ObjectId is designed to lightweight and easy to generate
** 12-bytes of storage (24 hexidecimal digits)
*** timestamp - byte 0-3
*** machine - byte 4-6
*** PID - byte 7-8
*** increment - byte 9-11
** _id is generated automatically if not present in document
 

== MongoDB Shell ==
<syntaxhighlight lang="JavaScript">
$ mongo
MongoDB shell version: 4.0.6
connecting to: test
>

$ mongo HostName:PortNumber/DatabaseName
$ mongo localhost:27017/test

$ mongo --nodb
> conn = new Mongo("localhost:27017")
connection to localhost27017
> db = conn.getDB("NobleProg")
NobleProg
</syntaxhighlight>
 

=== Using help ===
* mongo is a JavaScript shell, help is available in JavaScript on-line documentation
* use built-in help for MongoDB-specific functionality
* type function name without parentheses to see what the function is doing 

<syntaxhighlight lang="JavaScript">
> help
db.help() help on db methods
db.mycoll.help() help on collections methods
...
exit quit mongo shell
>
> db.NobleProg.stats
function ( scale ){
return this._db.runCommand( { collstats : this._shortName , scale : scale } );
}
>
> db.NobleProg.stats()
{ "ok" : 0, "errmsg" : "Collection [test.NobleProg] not found." }
>
</syntaxhighlight>
 

=== Running Scripts ===
* mongo can execute JavaScript files
* scripts have access to all global variables (e.g. "db")
* shell helpers (e.g. "show collections") do not work from files; use valid JavaScript equivalents (e.g. "db.getCollectionNames()")
* use --quiet to hide "MongoDB shell version..." when executing script
* use load() to run script directly from Mongo Shell
* use .mongorc.js for frequently-loaded scripts
** located in user home directory, run when starting up the shell, --norc to disable it
** useful also to customize prompt

<syntaxhighlight lang="JavaScript">
$ mongo script.js
MongoDB shell version: 4.0.6
connecting to: test
script.js was executed successfully!
$
$ mongo --quiet script.js
script.js was executed successfully!
$
$ mongo
MongoDB shell version: 4.0.6
connecting to: test
> load("script.js")
script.js was executed successfully!
>
</syntaxhighlight>
 

=== Editing Complex Variables ===
* limited multiline support in the shell
* external editors are allowed
* EDITOR="/usr/bin/gedit"
* EDITOR="c:\\windows\\notepad.exe"

<syntaxhighlight lang="JavaScript">
$ mongo --quiet
> EDITOR="c:\\windows\\notepad.exe"
> use training
switched to db training
> person = db.people.findOne()
{ "_id" : ObjectId("54568445cfc7c83518fa5430"), "Name" : "Sean Connery" }
> edit person
> person
{ "_id" : ObjectId("54568445cfc7c83518fa5430"), "Name" : "Sean Connery", "Nationality" : "Great Britain" }
> db.people.save(person)
</syntaxhighlight>

Basics of MongoDB - Revision history

Lsokolowski1: /* CRUD */

Lsokolowski1: /* CRUD */

Lsokolowski1: /* CRUD */

Lsokolowski1: /* CRUD */

Kbaran: /* MongoDB Shell */