[Couchdb Wiki] Update of "Views_for_SQL_Jockeys" by JoanTouzet

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The page "Views_for_SQL_Jockeys" has been deleted by JoanTouzet:

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- <>
  
- Please see the updated version of this page in our 
[[http://docs.couchdb.org/en/stable/ddocs/views/nosql.html|official 
documentation]].
- 

[Couchdb Wiki] Update of "Views_for_SQL_Jockeys" by JoanTouzet

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Dear Wiki user,

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The "Views_for_SQL_Jockeys" page has been changed by JoanTouzet:
https://wiki.apache.org/couchdb/Views_for_SQL_Jockeys?action=diff=7=8

  <>
  
- Please see the updated version of this page in our 
[[https://atypical.net/couchdb-documentation/ddocs/views/nosql.html|official 
documentation]].
+ Please see the updated version of this page in our 
[[http://docs.couchdb.org/en/stable/ddocs/views/nosql.html|official 
documentation]].
  

[Couchdb Wiki] Update of "Views_for_SQL_Jockeys" by JoanTouzet

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Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Couchdb Wiki" for 
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The "Views_for_SQL_Jockeys" page has been changed by JoanTouzet:
https://wiki.apache.org/couchdb/Views_for_SQL_Jockeys?action=diff=6=7

Comment:
Updated link

  <>
  
- This page now resides at 
http://books.couchdb.org/relax/reference/views-for-sql-jockeys instead.
+ Please see the updated version of this page in our 
[[https://atypical.net/couchdb-documentation/ddocs/views/nosql.html|official 
documentation]].
  

[Couchdb Wiki] Update of Views_for_SQL_Jockeys by JoanTouzet

[Apache Wiki]

Dear Wiki user,

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change notification.

The Views_for_SQL_Jockeys page has been changed by JoanTouzet:
http://wiki.apache.org/couchdb/Views_for_SQL_Jockeys?action=diffrev1=4rev2=5

Comment:
Removing outdated incomplete content in favour of the superior reference

  Include(EditTheWiki)
  
- The latest version is maintained at 
http://books.couchdb.org/relax/reference/views-for-sql-jockeys
+ This page now resides 
athttp://books.couchdb.org/relax/reference/views-for-sql-jockeys instead.
  
- 
- = View Cookbook for SQL Jockeys =
- 
- This is a collection of some common SQL queries and how to get the same 
result in CouchDB. The key to remember here is that CouchDB does not work like 
an SQL database at all and that best practices from the SQL world do not 
translate well or at all to CouchDB. This cookbook assumes that you are 
familiar with the CouchDB basics like creating and updating databases and 
documents.
- 
- == Using Views (CREATE / ALTER TABLE) ==
- 
- Using views is a two step process. First you ''define'' a view, then you 
''query'' it. This is analogous to defining a table structure (with indexes) 
using `CREATE TABLE` or `ALTER TABLE` and querying it using an SQL query.
- 
- === Defining a View ===
- 
- Defining a view is done by creating a special document in a CouchDB database. 
The only actual speciality is the `_id` of the document: it starts with 
`_design/`, for example `_design/application`. Other than that, it is just a 
regular CouchDB document. To make sure CouchDB understands that you are 
defining a view, you need to prepare the contents of that design document in a 
special format. Here is an example:
- 
- {{{
- {
-   _id: _design/application,
-   _rev: 1-C1687D17,
-   views: {
- viewname: {
-   map: function(doc) { ... },
-   reduce: function(keys, values) { ... }
- }
-   }
- }
- }}}
- 
- We are defining a view `viewname`. The definition of the view consists of two 
functions. The ''map function'' and the ''reduce function''. Specifying a 
reduce function is optional. We'll look at the nature of the functions later. 
Note that `viewname` can be whatever you like; `users`, `by-name`, or `by date` 
are just some examples.
- 
- A single design document can also include multiple view definitions, each 
identified by a unique name:
- 
- {{{
- {
-   _id: _design/application,
-   _rev: 1-C1687D17,
-   views: {
- viewname: {
-   map: function(doc) { ... },
-   reduce: function(keys, values) { ... }
- },
- anotherview: {
-   map: function(doc) { ... },
-   reduce: function(keys, values) { ... }
- }
-   }
- }
- }}}
- 
- === Querying a View ===
- 
- The name of the design document and the name of the view are significant for 
querying the view. To query the view `viewname` you perform a HTTP `GET` 
request to the following URI:
- 
- {{{
- /database/_design/application/_view/viewname
- }}}
- 
- `database` is the name of the database you created your design document in. 
Next up is the design document name and then the view name prefixed with 
`_view/`. To query `anotherview` replace `viewname` in that URI with 
`anotherview`. If you want to query a view in a different design document 
adjust the design document name.
- 
- 
- === Map  Reduce Functions ===
- 
- Map/Reduce is a concept that solves problems by applying a two-step process; 
aptly named the ''map'' phase and the 'reduce' phase. The map phase looks at 
all documents in CouchDB separately one after the other and creates a ''map 
result''. The map result is an ordered list of key-value pairs. Both key and 
value can be specified by the user writing the map function. A map function may 
call the built-in `emit(key, value)` function 0 to N times per document, 
creating a row in the map result per invocation.
- 
- CouchDB is smart enough to only run a map function once for every document, 
even on subsequent queries on a view. Only changes to documents, or new 
documents need to be processed anew.
- 
-  Map Functions 
- 
- Map functions run in isolation for every document. They can't modify the 
document and they can't talk to the outside world; they can't have 
''side-effects''. This is required so CouchDB can guarantee correct results 
without having to recalculate a complete result when only one document gets 
changed.
- 
- The map result looks like this:
- 
- {{{
- {total_rows:3,offset:0,rows:[
-   {id:fc2636bf50556346f1ce46b4bc01fe30,key:Lena,value:5},
-   {id:1fb2449f9b9d4e466dbfa47ebe675063,key:Lisa,value:4},
-   {id:8ede09f6f6aeb35d948485624b28f149,key:Sarah,value:6}
- }
- }}}
- 
- It is a list of rows sorted by the value of `key`. The `id` is added 
automatically and refers back to the document that created this row. The 
`value` is the data you're looking for. For example purposes, it's the girl's 
age.
- 
- The map function that produces this result is:
- 
- {{{
- function(doc) {
-   if(doc.name