Sig: Mongoose Sup: CoffeeScript y Express Ant: Pruebas Con:
Ind:
CONTACT table might include FIRST_NAME, LAST_NAME and IMAGE fields,
while the PHONE_NUMBER table might include COUNTRY_CODE, AREA_CODE,
PHONE_NUMBER and TYPE (home, work, etc).
PHONE_NUMBER table also
contains a foreign key field, "CONTACT_ID", which holds the unique ID
number assigned to the contact when it was created.
COUNTRY_FLAG to a CONTACT, simply add this field to new documents
as they are inserted, this will have no effect on the database or the
existing documents already stored, they simply won't have this field
address book entry, which allows the programmer to retrieve related
types of information, like all the address book entries
$ mongod all output going to: /usr/local/var/log/mongodb/mongo.log
By default, mongo looks for a database server listening on port 27017 on the localhost interface.
To connect to a server on a different port
or interface, use the --port and
--host options.
Podemos también usar un fichero de configuración:
[~/javascript/expressjs/coffee-mongo(master)]$ cat /usr/local/etc/mongod.conf # Store data in /usr/local/var/mongodb instead of the default /data/db dbpath = /usr/local/var/mongodb # Append logs to /usr/local/var/log/mongodb/mongo.log logpath = /usr/local/var/log/mongodb/mongo.log logappend = true verbose = v # Only accept local connections bind_ip = 127.0.0.1
y ejecutarlo con la opción --config:
$ mongod --config /usr/local/etc/mongod.conf
[~/src/coffee/coffeepress.bak(master)]$ mongo MongoDB shell version: 2.4.8 connecting to: test Server has startup warnings: Mon Apr 13 21:53:16.204 [initandlisten] Mon Apr 13 21:53:16.204 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000
After starting the mongo shell, your session will use the test database by default. At any time, issue the following operation at the mongo shell to report the name of the current database:
> db test
From the mongo shell, display the list of databases, with the following operation:
> show dbs coffeepress 0.203125GB coffeepress-dev 0.203125GB dict_dev 0.203125GB example 0.203125GB local 0.078125GB mean 0.203125GB my_perpetuity_database 0.203125GB mydb 0.203125GB sinatra-example-dev 0.203125GB test 0.203125GB
Switch to a new database named example,
with the following operation:
> use example switched to db exampleAt any point, you can access help for the mongo shell using
> help
db.help() help on db methods
db.mycoll.help() help on collection methods
sh.help() sharding helpers
rs.help() replica set helpers
help admin administrative help
help connect connecting to a db help
help keys key shortcuts
help misc misc things to know
help mr mapreduce
show dbs show database names
show collections show collections in current database
show users show users in current database
show profile show most recent system.profile entries with time >= 1ms
show logs show the accessible logger names
show log [name] prints out the last segment of log in memory, 'global' is default
use <db_name> set current database
db.foo.find() list objects in collection foo
db.foo.find( { a : 1 } ) list objects in foo where a == 1
it result of the last line evaluated; use to further iterate
DBQuery.shellBatchSize = x set default number of items to display on shell
exit quit the mongo shell
Furthermore, you can append the .help()
method to some JavaScript methods, any cursor object,
as well as the db and db.collection objects to return additional help information.
> db.help()
DB methods:
db.addUser(userDocument)
db.auth(username, password)
...
testData
within the new database named mydb.
Create two documents named j and
k by using the following sequence of JavaScript operations:
> j = { name : "mongo" }
{ "name" : "mongo" }
> k = { x : 3 }
{ "x" : 3 }
Insert the j and k documents into the
testData collection with the following sequence of operations:
> db.testData.insert( j ) > db.testData.insert( k )When you insert the first document, the
mongod
will create both the mydb
database and the testData collection.
> show collections system.indexes testDataThe mongo shell will return the list of the collections in the current (i.e. mydb) database. At this point, the only collection with user data is testData.
Confirm that the documents exist in the testData collection by issuing a query on the collection using the find() method:
> db.testData.find()
{ "_id" : ObjectId("552d751969c6f61bfbe4e6ed"), "name" : "mongo" }
{ "_id" : ObjectId("552d751a69c6f61bfbe4e6ee"), "x" : 3 }
All MongoDB documents must have an _id field with a unique value. These operations do not explicitly specify a value for the _id field, so mongo creates a unique ObjectId value for the field before inserting it into the collection.
From the mongo shell, use the for loop. If the testData collection does not exist, MongoDB will implicitly create the collection.
> for (var i = 1; i <= 25; i++) {
... db.testData.insert( { x : i } )
... }
Use find() to query the collection:
> db.testData.find()
{ "_id" : ObjectId("552d751969c6f61bfbe4e6ed"), "name" : "mongo" }
{ "_id" : ObjectId("552d751a69c6f61bfbe4e6ee"), "x" : 3 }
{ "_id" : ObjectId("552d791269c6f61bfbe4e6f0"), "x" : 1 }
{ "_id" : ObjectId("552d791269c6f61bfbe4e6f1"), "x" : 2 }
{ "_id" : ObjectId("552d791269c6f61bfbe4e6f2"), "x" : 3 }
....
{ "_id" : ObjectId("552d791269c6f61bfbe4e701"), "x" : 18 }
Type "it" for more
Iterate through the cursor.
The find() method returns a cursor. To iterate the cursor and return more documents, type
it in the mongo shell. The shell will exhaust the cursor and return these documents:
> it
{ "_id" : ObjectId("552d791269c6f61bfbe4e702"), "x" : 19 }
.....
{ "_id" : ObjectId("552d791269c6f61bfbe4e708"), "x" : 25 }
When you query a collection, MongoDB returns a “cursor” object that contains the results of the query. The mongo shell then iterates over the cursor to display the results. Rather than returning all results at once, the shell iterates over the cursor 20 times to display the first 20 results and then waits for a request to iterate over the remaining results. In the shell, enter it to iterate over the next set of results.
The procedures in this section show other ways to work with a cursor. For comprehensive documentation on cursors, see Iterate the Returned Cursor.
Casiano Rodríguez León