Category: couchdb

CouchDB – Quick Guide ”; Previous Next CouchDB – Introduction Database management system provides mechanism for storage and retrieval of data. There are three main types of database management systems namely RDBMS (Relational Database management Systems), OLAP (Online Analytical Processing Systems) and NoSQL. RDBMS RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems like MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. A Relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd. The data in RDBMS is stored in database objects called tables. The table is a collection of related data entries and it consists of columns and rows. It stores only structured data. OLAP Online Analytical Processing Server (OLAP) is based on the multidimensional data model. It allows managers and analysts to get an insight of the information through fast, consistent, and interactive access to information. NoSQL Databases A NoSQL database (sometimes called as Not Only SQL) is a database that provides a mechanism to store and retrieve data other than the tabular relations used in relational databases. These databases are schema-free, support easy replication, have simple API, eventually consistent, and can handle huge amounts of data (big data). The primary objective of a NoSQL database is to have the following − Simplicity of design, Horizontal scaling, and Finer control over availability. NoSQL databases use different data structures compared to relational databases. It makes some operations faster in NoSQL. The suitability of a given NoSQL database depends on the problem it must solve. These databases store both structured data and unstructured data like audio files, video files, documents, etc. These NoSQL databases are classified into three types and they are explained below. Key-value Store − These databases are designed for storing data in key-value pairs and these databases will not have any schema. In these databases, each data value consists of an indexed key and a value for that key. Examples − BerkeleyDB, Cassandra, DynamoDB, Riak. Column Store − In these databases, data is stored in cells grouped in columns of data, and these columns are further grouped into Column families. These column families can contain any number of columns. Examples − BigTable, HBase, and HyperTable. Document Store − These are the databases developed on the basic idea of key-value stores where “documents” contain more complex data. Here, each document is assigned a unique key, which is used to retrieve the document. These are designed for storing, retrieving, and managing document-oriented information, also known as semi-structured data. Examples − CouchDB and MongoDB. What is CouchDB? CouchDB is an open source database developed by Apache software foundation. The focus is on the ease of use, embracing the web. It is a NoSQL document store database. It uses JSON, to store data (documents), java script as its query language to transform the documents, http protocol for api to access the documents, query the indices with the web browser. It is a multi master application released in 2005 and it became an apache project in 2008. Why CouchDB? CouchDB have an HTTP-based REST API, which helps to communicate with the database easily. And the simple structure of HTTP resources and methods (GET, PUT, DELETE) are easy to understand and use. As we store data in the flexible document-based structure, there is no need to worry about the structure of the data. Users are provided with powerful data mapping, which allows querying, combining, and filtering the information. CouchDB provides easy-to-use replication, using which you can copy, share, and synchronize the data between databases and machines. Data Model Database is the outermost data structure/container in CouchDB. Each database is a collection of independent documents. Each document maintains its own data and self-contained schema. Document metadata contains revision information, which makes it possible to merge the differences occurred while the databases were disconnected. CouchDB implements multi version concurrency control, to avoid the need to lock the database field during writes. Features of CouchDB:Reduce the Content Document Storage CouchDB is a document storage NoSQL database. It provides the facility of storing documents with unique names, and it also provides an API called RESTful HTTP API for reading and updating (add, edit, delete) database documents. In CouchDB, documents are the primary unit of data and they also include metadata. Document fields are uniquely named and contain values of varying types (text, number, Boolean, lists, etc.), and there is no set limit to text size or element count. Document updates (add, edit, delete) follow Atomicity, i.e., they will be saved completely or not saved at all. The database will not have any partially saved or edited documents. Json Document Structure { “field” : “value”, “field” : “value”, “field” : “value”, } ACID Properties CouchDB contains ACID properties as one of its features. Consistency − When the data in CouchDB was once committed, then this data will not be modified or overwritten. Thus, CouchDB ensures that the database file will always be in a consistent state. A multi-Version Concurrency Control (MVCC) model is used by CouchDB reads, because of which the client will see a consistent snapshot of the database from the beginning to the end of the read operation. Whenever a documents is updated, CouchDB flushes the data into the disk, and the updated database header is written in two consecutive and identical chunks to make up the first 4k of the file, and then synchronously flushed to disk. Partial updates during the flush will be discarded. If the failure occurred while committing the header, a surviving copy of the previous identical headers will remain, ensuring coherency of all previously committed data. Except the header area, consistency checks or fix-ups after a crash or a power failure are never necessary. Compaction Whenever the space in the database file got wasted above certain extent, all the active data will be copied (cloned) to a new file. When the

CouchDB – Useful Resources ”; Previous Next The following resources contain additional information on CouchDB. Please use them to get more in-depth knowledge on this topic. Full Stack Web Development Course Best Seller 208 Lectures 33 hours Eduonix Learning Solutions More Detail IBM Cloudant – NoSQL Database 20 Lectures 2 hours Harshit Srivastava More Detail AWS and IBM Databases on Cloud 34 Lectures 3 hours Harshit Srivastava More Detail Print Page Previous Next Advertisements ”;

CouchDB – Creating a Document ”; Previous Next Documents are CouchDB’s central data structure. Contents of the database will be stored in the form of Documents instead of tables. You can create these documents using cURL utility provided by CouchDB, as well as Futon. This chapter covers the ways to create a document in a database. Each document in CouchDB has a unique ID. You can choose your own ID that should be in the form of a string. Generally, UUID (Universally Unique IDentifier) is used, which are random numbers that have least chance of creating a duplicate. These are preferred to avoid collisions. Creating a Document using cURL Utility You can create a document in CouchDB by sending an HTTP request to the server using PUT method through cURL utility. Following is the syntax to create a document. $ curl -X PUT http://127.0.0.1:5984/database name/”id” -d ” { document} ” Using −X, we can specify a custom request method of HTTP we are using, while communicating with the HTTP server. In this case, we are using PUT method. When we use the PUT method, the content of the url specifies the object name we are creating using the HTTP request. Here we have to send the following − The name of the database name in which we are creating the document. The document id. The data of the document. −d option is used to send the data/document through HTTP request. While writing a document simply enter your Field-Value pairs separated by colon, within flower brackets as shown below − { Name : Raju age : 23 Designation : Designer } Example Using the above given syntax if you want to create a document with id 001 in a database with name my_database, you can create it as shown below. $ curl -X PUT http://127.0.0.1:5984/my_database/”001″ -d ”{ ” Name ” : ” Raju ” , ” age ” :” 23 ” , ” Designation ” : ” Designer ” }” {“ok”:true,”id”:”001″,”rev”:”1-1c2fae390fa5475d9b809301bbf3f25e”} The response of CouchDB to this request contains three fields − “ok”, indicating the operation was successful. “id”, which stores the id of the document and “rev”, this indicates the revision id. Every time you revise (update or modify) a document a _rev value will be generated by CouchDB. If you want to update or delete a document, CouchDB expects you to include the _rev field of the revision you wish to change. When CouchDB accepts the change, it will generate a new revision number. This mechanism ensures concurrency control. Verification If you want to view the created document you can get it using the document as shown below. $ curl -X GET http://127.0.0.1:5984/my_database/001 { “_id”: “001”, “_rev”: “1-3fcc78daac7a90803f0a5e383f4f1e1e”, “Name”: “Raju”, “age”: 23, “Designation”: “Designer” } Creating a Document using Futon To Create a document open the http://127.0.0.1:5984/_utils/ url to get an Overview/index page of CouchDB as shown below. Select the database in which you want to create the document. Open the Overview page of the database and select New Document option as shown below. When you select the New Document option, CouchDB creates a new database document, assigning it a new id. You can edit the value of the id and can assign your own value in the form of a string. In the following illustration, we have created a new document with an id 001. In this page, you can observe three options − save Document, Add Field and Upload Attachment. Add Field to the Document To add field to the document click on Add Field option. After creating a database, you can add a field to it using this option. Clicking on it will get you a pair of text boxes, namely, Field, value. You can edit these values by clicking on them. Edit those values and type your desired Field-Value pair. Click on the green button to save these values. In the following illustration, we have created three fields Name, age and, Designation of the employee. Save Document You can save the changes made to the document by clicking on this option. After saving, a new id _rev will be generated as shown below. Print Page Previous Next Advertisements ”;

CouchDB – Attaching Files ”; Previous Next Attaching Files using cURL You can attach files to CouchDB just like email. The file contains metadata like name and includes its MIME type, and the number of bytes the attachment contains. To attach files to a document you have to send PUT request to the server. Following is the syntax to attach files to the document − $ curl -vX PUT http://127.0.0.1:5984/database_name/database_id /filename?rev=document rev_id –data-binary @filename -H “Content-Type: type of the content” The request has various options that are explained below. –data-binary@ − This option tells cURL to read a file’s contents into the HTTP request body. -H − This option is used to mention the content type of the file we are going to upload. Example Let us attach a file named boy.jpg, to the document with id 001, in the database named my_database by sending PUT request to CouchDB. Before that, you have to fetch the data of the document with id 001 to get its current rev id as shown below. $ curl -X GET http://127.0.0.1:5984/my_database/001 { “_id”: “001”, “_rev”: “1-967a00dff5e02add41819138abb3284d” } Now using the _rev value, send the PUT request to the CouchDB server as shown below. $ curl -vX PUT http://127.0.0.1:5984/my_database/001/boy.jpg?rev=1- 967a00dff5e02add41819138abb3284d –data-binary @boy.jpg -H “ContentType: image/jpg” Verification To verify whether the attachment is uploaded, fetch the document content as shown below− $ curl -X GET http://127.0.0.1:5984/my_database/001 { “_id”: “001”, “_rev”: “2-4705a219cdcca7c72aac4f623f5c46a8”, “_attachments”: { “boy.jpg”: { “content_type”: “image/jpg”, “revpos”: 2, “digest”: “md5-9Swz8jvmga5mfBIsmCxCtQ==”, “length”: 91408, “stub”: true } } } Attaching Files using Futon Upload Attachment Using this option, you can upload a new attachment such as a file, image, or document, to the database. To do so, click on the Upload Attachment button. A dialog box will appear where you can choose the file to be uploaded. Select the file and click on the Upload button. The file uploaded will be displayed under _attachments field. Later you can see the file by clicking on it. Print Page Previous Next Advertisements ”;

CouchDB – Creating a Database ”; Previous Next Database is the outermost data structure in CouchDB where your documents are stored. You can create these databases using cURL utility provided by CouchDB, as well as Futon the web interface of CouchDB. Creating a Database using cURL Utility You can create a database in CouchDB by sending an HTTP request to the server using PUT method through cURL utility. Following is the syntax to create a database − $ curl -X PUT http://127.0.0.1:5984/database name Using −X we can specify HTTP custom request method to be used. In this case, we are using PUT method. When we use the PUT operation/method, the content of the url specifies the object name we are creating using HTTP request. Here we have to send the name of the database using put request in the url to create a database. Example Using the above given syntax if you want to create a database with name my_database, you can create it as follows curl -X PUT http://127.0.0.1:5984/my_database { “ok”:true } As a response the server will return you a JSON document with content “ok” − true indicating the operation was successful. Verification Verify whether the database is created, by listing out all the databases as shown below. Here you can observe the name of a newly created database, ” my_database “ in the list. $ curl -X GET http://127.0.0.1:5984/_all_dbs [ “_replicator ” , ” _users ” , ” my_database ” ] Creating a Database using Futon To create a database open the http://127.0.0.1:5984/_utils/. You will get an Overview/index page of CouchDB as shown below. In this page, you can see the list of databases in CouchDB, an option button Create Database on the left hand side. Now click on the create database link. You can see a popup window Create New Databases asking for the database name for the new database. Choose any name following the mentioned criteria. Here we are creating another database with name tutorials_point. Click on the create button as shown in the following screenshot. Print Page Previous Next Advertisements ”;

CouchDB – Deleting a Document ”; Previous Next Deleting a Document using cURL Utility You can delete a document in CouchDB by sending an HTTP request to the server using DELETE method through cURL utility. Following is the syntax to delete a document. curl -X DELETE http : // 127.0.0.1:5984 / database name/database id?_rev id Using −X, we can specify a custom request method of HTTP we are using, while communicating with the HTTP server. In this case, we are using Delete method. To delete a database /database_name/database_id/ is not enough. You have to pass the recent revision id through the url. To mention attributes of any data structure “?” is used. Example Suppose there is a document in database named my_database with document id 001. To delete this document, you have to get the rev id of the document. Get the document data as shown below. $ curl -X GET http://127.0.0.1:5984/my_database/001 { ” _id ” : ” 001 “, ” _rev ” : ” 2-04d8eac1680d237ca25b68b36b8899d3 ” , ” age ” : ” 23 ” } Now specify the revision id of the document to be deleted, id of the document, and database name the document belongs to, as shown below − $ curl -X DELETE http://127.0.0.1:5984/my_database/001?rev=1- 3fcc78daac7a90803f0a5e383f4f1e1e {“ok”:true,”id”:”001″,”rev”:”2-3a561d56de1ce3305d693bd15630bf96″} Verification To verify whether the document is deleted, try to fetch the document by using the GET method. Since you are fetching a deleted document, this will give you an error message as shown below − $ curl -X GET http://127.0.0.1:5984/my_database/001 {“error”:”not_found”,”reason”:”deleted”} Deleting a Document using Futon First of all, verify the documents in the database. Following is the snapshot of the database named tutorials_point. Here you can observe, the database consists of three documents. To delete any of the documents say 003, do the following − Click on the document, you will get a page showing the contents of selected document in the form of field-value pairs. This page also contains four options namely Save Document, Add Field, Upload Attachment, Delete Document. Click on Delete Document option. You will get a dialog box saying “Are you sure you want to delete this document?” Click on delete, to delete the document. Print Page Previous Next Advertisements ”;

CouchDB – Installation ”; Previous Next This chapter teaches you how to install CouchDB in windows as well as Linux systems. Installing CouchDB in Windows Download CouchDB The official website for CouchDB is https://couchdb.apache.org. If you click the given link, you can get the home page of the CouchDB official website as shown below. If you click on the download button that will lead to a page where download links of CouchDB in various formats are provided. The following snapshot illustrates the same. Choose the download link for windows systems and select one of the provided mirrors to start your download. Installing CouchDB CouchDB will be downloaded to your system in the form of setup file named setup-couchdb-1.6.1_R16B02.exe. Run the setup file and proceed with the installation. After installation, open built-in web interface of CouchDB by visiting the following link: http://127.0.0.1:5984/. If everything goes fine, this will give you a web page, which have the following output. { “couchdb”:”Welcome”,”uuid”:”c8d48ac61bb497f4692b346e0f400d60″, “version”:”1.6.1″, “vendor”:{ “version”:”1.6.1″,”name”:”The Apache Software Foundation” } } You can interact with the CouchDB web interface by using the following url − http://127.0.0.1:5984/_utils/ This shows you the index page of Futon, which is the web interface of CouchDB. Installing CouchDB in Linux Systems For many of the Linux flavored systems, they provide CouchDB internally. To install this CouchDB follow the instructions. On Ubuntu and Debian you can use − sudo aptitude install couchdb On Gentoo Linux there is a CouchDB ebuild available − sudo emerge couchdb If your Linux system does not have CouchDB, follow the next section to install CouchDB and its dependencies. Installing CouchDB Dependencies Following is the list of dependencies that are to be installed to get CouchDB in your system− Erlang OTP ICU OpenSSL Mozilla SpiderMonkey GNU Make GNU Compiler Collection libcurl help2man Python for docs Python Sphinx To install these dependencies, type the following commands in the terminal. Here we are using Centos 6.5 and the following commands will install the required softwares compatible to Centos 6.5. $sudo yum install autoconf $sudo yum install autoconf-archive $sudo yum install automake $sudo yum install curl-devel $sudo yum install erlang-asn1 $sudo yum install erlang-erts $sudo yum install erlang-eunit $sudo yum install erlang-os_mon $sudo yum install erlang-xmerl $sudo yum install help2man $sudo yum install js-devel $sudo yum install libicu-devel $sudo yum install libtool $sudo yum install perl-Test-Harness Note − For all these commands you need to use sudo. The following procedure converts a normal user to a sudoer. Login as root in admin user Open sudo file using the following command − visudo Then edit as shown below to give your existing user the sudoer privileges − Hadoop All=(All) All , and press esc : x to write the changes to the file. After downloading all the dependencies in your system, download CouchDB following the given instructions. Downloading CouchDB Apache software foundation will not provide the complete .tar file for CouchDB, so you have to install it from the source. Create a new directory to install CouchDB, browse to such created directory and download CouchDB source by executing the following commands − $ cd $ mkdir CouchDB $ cd CouchDB/ $ wget http://www.google.com/url?q=http%3A%2F%2Fwww.apache.org%2Fdist%2Fcouchdb%2Fsource%2F1.6.1%2Fapache-couchdb-1.6.1.tar.gz This will download CouchDB source file into your system. Now unzip the apache-couchdb-1.6.1.tar.gz as shown below. $ tar zxvf apache-couchdb-1.6.1.tar.gz Configuring CouchDB To configure CouchDB, do the following − Browse to the home folder of CouchDB. Login as superuser. Configure using ./configure prompt as shown below − $ cd apache-couchdb-1.6.1 $ su Password: # ./configure –with-erlang=/usr/lib64/erlang/usr/include/ It gives you the following output similar to that shown below with a concluding line saying − You have configured Apache CouchDB, time to relax. # ./configure –with-erlang=/usr/lib64/erlang/usr/include/ checking for a BSD-compatible install… /usr/bin/install -c checking whether build environment is sane… yes checking for a thread-safe mkdir -p… /bin/mkdir -p checking for gawk… gawk checking whether make sets $(MAKE)… yes checking how to create a ustar tar archive… gnutar ……………………………………………………….. ………………………. config.status: creating var/Makefile config.status: creating config.h config.status: config.h is unchanged config.status: creating src/snappy/google-snappy/config.h config.status: src/snappy/google-snappy/config.h is unchanged config.status: executing depfiles commands config.status: executing libtool commands You have configured Apache CouchDB, time to relax. Run `make && sudo make install” to install. Installing CouchDB Now type the following command to install CouchDB in your system. # make && sudo make install It installs CouchDB in your system with a concluding line saying − You have installed Apache CouchDB, time to relax. Starting CouchDB To start CouchDB, browse to the CouchDB home folder and use the following command − $ cd apache-couchdb-1.6.1 $ cd etc $ couchdb start It starts CouchDB giving the following output: − Apache CouchDB 1.6.1 (LogLevel=info) is starting. Apache CouchDB has started. Time to relax. [info] [lt;0.31.0gt;] Apache CouchDB has started on http://127.0.0.1:5984/ [info] [lt;0.112.0gt;] 127.0.0.1 – – GET / 200 [info] [lt;0.112.0gt;] 127.0.0.1 – – GET /favicon.ico 200 Verification Since CouchDB is a web interface, try to type the following homepage url in the browser. http://127.0.0.1:5984/ It produces the following output − { “couchdb”:”Welcome”, “uuid”:”8f0d59acd0e179f5e9f0075fa1f5e804″, “version”:”1.6.1″, “vendor”:{ “name”:”The Apache Software Foundation”, “version”:”1.6.1″ } } Print Page Previous Next Advertisements ”;

CouchDB – Introduction ”; Previous Next Database management system provides mechanism for storage and retrieval of data. There are three main types of database management systems namely RDBMS (Relational Database management Systems), OLAP (Online Analytical Processing Systems) and NoSQL. RDBMS RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems like MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. A Relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd. The data in RDBMS is stored in database objects called tables. The table is a collection of related data entries and it consists of columns and rows. It stores only structured data. OLAP Online Analytical Processing Server (OLAP) is based on the multidimensional data model. It allows managers and analysts to get an insight of the information through fast, consistent, and interactive access to information. NoSQL Databases A NoSQL database (sometimes called as Not Only SQL) is a database that provides a mechanism to store and retrieve data other than the tabular relations used in relational databases. These databases are schema-free, support easy replication, have simple API, eventually consistent, and can handle huge amounts of data (big data). The primary objective of a NoSQL database is to have the following − Simplicity of design, Horizontal scaling, and Finer control over availability. NoSQL databases use different data structures compared to relational databases. It makes some operations faster in NoSQL. The suitability of a given NoSQL database depends on the problem it must solve. These databases store both structured data and unstructured data like audio files, video files, documents, etc. These NoSQL databases are classified into three types and they are explained below. Key-value Store − These databases are designed for storing data in key-value pairs and these databases will not have any schema. In these databases, each data value consists of an indexed key and a value for that key. Examples − BerkeleyDB, Cassandra, DynamoDB, Riak. Column Store − In these databases, data is stored in cells grouped in columns of data, and these columns are further grouped into Column families. These column families can contain any number of columns. Examples − BigTable, HBase, and HyperTable. Document Store − These are the databases developed on the basic idea of key-value stores where “documents” contain more complex data. Here, each document is assigned a unique key, which is used to retrieve the document. These are designed for storing, retrieving, and managing document-oriented information, also known as semi-structured data. Examples − CouchDB and MongoDB. What is CouchDB? CouchDB is an open source database developed by Apache software foundation. The focus is on the ease of use, embracing the web. It is a NoSQL document store database. It uses JSON, to store data (documents), java script as its query language to transform the documents, http protocol for api to access the documents, query the indices with the web browser. It is a multi master application released in 2005 and it became an apache project in 2008. Why CouchDB? CouchDB have an HTTP-based REST API, which helps to communicate with the database easily. And the simple structure of HTTP resources and methods (GET, PUT, DELETE) are easy to understand and use. As we store data in the flexible document-based structure, there is no need to worry about the structure of the data. Users are provided with powerful data mapping, which allows querying, combining, and filtering the information. CouchDB provides easy-to-use replication, using which you can copy, share, and synchronize the data between databases and machines. Data Model Database is the outermost data structure/container in CouchDB. Each database is a collection of independent documents. Each document maintains its own data and self-contained schema. Document metadata contains revision information, which makes it possible to merge the differences occurred while the databases were disconnected. CouchDB implements multi version concurrency control, to avoid the need to lock the database field during writes. Features of CouchDB:Reduce the Content Document Storage CouchDB is a document storage NoSQL database. It provides the facility of storing documents with unique names, and it also provides an API called RESTful HTTP API for reading and updating (add, edit, delete) database documents. In CouchDB, documents are the primary unit of data and they also include metadata. Document fields are uniquely named and contain values of varying types (text, number, Boolean, lists, etc.), and there is no set limit to text size or element count. Document updates (add, edit, delete) follow Atomicity, i.e., they will be saved completely or not saved at all. The database will not have any partially saved or edited documents. Json Document Structure { “field” : “value”, “field” : “value”, “field” : “value”, } ACID Properties CouchDB contains ACID properties as one of its features. Consistency − When the data in CouchDB was once committed, then this data will not be modified or overwritten. Thus, CouchDB ensures that the database file will always be in a consistent state. A multi-Version Concurrency Control (MVCC) model is used by CouchDB reads, because of which the client will see a consistent snapshot of the database from the beginning to the end of the read operation. Whenever a documents is updated, CouchDB flushes the data into the disk, and the updated database header is written in two consecutive and identical chunks to make up the first 4k of the file, and then synchronously flushed to disk. Partial updates during the flush will be discarded. If the failure occurred while committing the header, a surviving copy of the previous identical headers will remain, ensuring coherency of all previously committed data. Except the header area, consistency checks or fix-ups after a crash or a power failure are never necessary. Compaction Whenever the space in the database file got wasted above certain extent, all the active data will be copied (cloned) to a new file. When the copying process is entirely

CouchDB – HTTP API ”; Previous Next Using HTTP request headers, you can communicate with CouchDB. Through these requests we can retrieve data from the database, store data in to the database in the form of documents, and we can view as well as format the documents stored in a database. HTTP Request Formats While communicating with the database we will use different request formats like get, head, post, put, delete, and copy. For all operations in CouchDB, the input data and the output data structures will be in the form of JavaScript Object Notation (JSON) object. Following are the different request formats of HTTP Protocol used to communicate with CouchDB. GET − This format is used to get a specific item. To get different items, you have to send specific url patterns. In CouchDB using this GET request, we can get static items, database documents and configuration, and statistical information in the form of JSON documents (in most cases). HEAD − The HEAD method is used to get the HTTP header of a GET request without the body of the response. POST − Post request is used to upload data. In CouchDB using POST request, you can set values, upload documents, set document values, and can also start certain administration commands. PUT − Using PUT request, you can create new objects, databases, documents, views and design documents. DELETE − Using DELETE request, you can delete documents, views, and design documents. COPY − Using COPY method, you can copy documents and objects. HTTP Request Headers HTTP headers should be supplied to get the right format and encoding. While sending the request to the CouchDB server, you can send Http request headers along with the request. Following are the different Http request headers. Content-type − This Header is used to specify the content type of the data that we supply to the server along with the request. Mostly the type of the content we send along with the request will be MIME type or JSON (application/json). Using Content-type on a request is highly recommended. Accept − This header is used to specify the server, the list of data types that client can understand, so that the server will send its response using those data types. Generally here, you can send the list of MIME data types the client accepts, separated by colons. Though, using Accept in queries of CouchDB is not required, it is highly recommended to ensure that the data returned can be processed by the client. Response Headers These are the headers of the response sent by the server. These headers give information about the content send by the server as response. Content-type − This header specifies the MIME type of the data returned by the server. For most request, the returned MIME type is text/plain. Cache-control − This header suggests the client about treating the information sent by the server. CouchDB mostly returns the must-revalidate, which indicates that the information should be revalidated if possible. Content-length − This header returns the length of the content sent by the server, in bytes. Etag − This header is used to show the revision for a document, or a view. Status Codes Following is the tabular form of the status code sent by the http header and the description of it. Sr.No. Status Code & Description 1 200 − OK This status will be issued when a request completed successfully. 2 201 − Created This status will be issued when a document is created. 3 202 − Accepted This status will be issued when a request is accepted. 4 404 − Not Found This status will be issued when the server is unable to find the requested content. 5 405 − Resource Not Allowed This status is issued when the HTTP request type used is invalid. 6 409 − Conflict This status is issued whenever there is any update conflict. 7 415 − Bad Content Type This status indicated that the requested content type is not supported by the server. 8 500 − Internal Server Error This status is issued whenever the data sent in the request is invalid. HTTP URL Paths There are certain url paths using which, you can interact with the database directly. Following is the tabular format of such url paths. Sr.No. URL & Operation 1 PUT /db This url is used to create a new database. 2 GET /db This url is used to get the information about the existing database. 3 PUT /db/document This url is used to create a document/update an existing document. 4 GET /db/document This url is used to get the document. 5 DELETE /db/document This url is used to delete the specified document from the specified database. 6 GET /db/_design/design-doc This url is used to get the definition of a design document. 7 GET /db/_design/designdoc/_view/view-name This url is used to access the view, view-name from the design document from the specified database. Print Page Previous Next Advertisements ”;

CouchDB – Deleting a Database ”; Previous Next Deleting a Database using cURL Utility You can delete a database in CouchDB by sending a request to the server using DELETE method through cURL utility. Following is the syntax to create a database − $ curl -X DELETE http://127.0.0.1:5984/database name Using −X we can specify a custom request method of HTTP we are using, while communicating with the HTTP server. In this case, we are using the DELETE method. Send the url to the server by specifying the database to be deleted in it. Example Assume there is a database named my_database2 in CouchDB. Using the above given syntax if you want to delete it, you can do it as follows − $ curl -X DELETE http://127.0.0.1:5984/my_database2 { “ok” : true } As a response, the server will return you a JSON document with content “ok” − true indicating the operation was successful. Verification Verify whether the database is deleted by listing out all the databases as shown below. Here you can observe the name of the deleted database, “my_database” is not there in the list. $ curl -X GET http://127.0.0.1:5984/_all_dbs [ “_replicator ” , ” _users ” ] Deleting a Database using Futon To delete a database, open the http://127.0.0.1:5984/_utils/ url where you will get an Overview/index page of CouchDB as shown below. Here you can see three user created databases. Let us delete the database named tutorials_point2. To delete a database, select one from the list of databases, and click on it, which will lead to the overview page of the selected database where you can see the various operations on databases. The following screenshot shows the same − Among them you can find Delete Database option. By clicking on it you will get a popup window, asking whether you are sure! Click on delete, to delete the selected database. Print Page Previous Next Advertisements ”;