Couchdb Study Notes

Couchdb is an easy-to-use nosql database. Download and install it on the official website, start it, and create a new JS file:

 
VaR HTTP = require ('http'); var Options = {port: 5984, method: 'get', // path: "/_ all_dbs "}; // This callback has only one parameter, namely HTTP. createserver (function (req, Res) {}) var Req = http. request (options, function (RES) {console. log ('status: '+ Res. statuscode); console. log ('headers: '+ JSON. stringify (res. headers); Res. setencoding ('utf8'); var body = "" res. on ('data', function (chunk) {body + = chunk}); Res. once ("end", function () {var JSON = JSON. parse (body); console. log (JSON)}; req. end () req. on ('error', function (e) {console. log ('problem with request: '+ E. message );});
 

Then open it with node. JS! The console outputs the following message, indicating that the message is successful:

Status: 200 headers: {"server": "couchdb/1.2.0 (Erlang OTP/r14b04)", "date": "Fri, 24 Aug 2:20:53:18 GMT ", "Content-Type": "text/plain; charset = UTF-8", "Content-Length": "40", "cache-control ": "must-revalidate"} {couchdb: 'Welcome ', version: '1. 2.0 '}
 

Then, modify the options object and check the number of databases in it.

 
VaR Options = {port: 5984, method: 'get', path: "/_ all_dbs "};
 

Will output an array

 
['_ Replicator', '_ users']
 

Create a database, which is a put request and the path is the database name.

 
VaR Options = {port: 5984, method: 'put', path: "/AAA "};
 

Output OK = true indicates success

 
{OK: true}
 

Note: The same database cannot be created again. If we try to send the above request again, the above request will be returned.

{Error: 'file _ exists', reason: 'The database cocould not be created, the file already exists .'}
 

To delete a database, use the Delete request. The path is the database name.

 
VaR Options = {port: 5984, method: 'delete', path: "/AAA "};
 

Insert a record in a database. Because the above AAA is deleted, we will create another albums.

 
VaR Options = {port: 5984, method: 'put', path: "/albums "};
 

Insert a new record. Most of the records in a nosql database are referred to as documents. It requires a uuid. You just need to create one.

VaR HTTP = require ('http'); // create a database named baseball var Options = {port: 5984, method: 'put', path: "/albums/1"}; var Req = http. request (options, function (RES) {console. log ('status: '+ Res. statuscode); console. log ('headers: '+ JSON. stringify (res. headers); Res. setencoding ('utf8'); var body = "" res. on ('data', function (chunk) {body + = chunk}); Res. once ("end", function () {var JSON = JSON. parse (body); console. log (JSON)}; req. setheader ("Content-Type", "application/JSON") // Add req to the document content. write (JSON. stringify ({"title": "There is nothing left to lose", "artist": "Foo Fighters"}) req. end () req. on ('error', function (e) {console. log ('problem with request: '+ E. message );});
 

Of course, the uuid created above is too insecure, so you can use couthdb to give your UUID

 
VaR Options = {port: 5984, method: 'get', path: "/_ uuids "};
 

Let's take out the saved document, that is, the database with id name and get request.

 
VaR Options = {port: 5984, method: 'get', path: "/albums/1 "};