Couchdb example: basics

This can be a lot to take in, so here is an example using curl and cdbcli.

NOTE:

in retrospect, I would have used curl exclusively

NOTE:

also note that JSON does not support comments

Create a database, and 4x documents

cdbcli

mkdir test_database
cd    test_database

touch will
# {
#   "name":      "will",
#   "age' :      30,
#   "shoesize" : 13,
# }

touch alex
# {
#   "name":      "alex",
#   "age' :      26,
#   "shoesize" :  9,
# }

touch zaphod
# (zaphod has no shoesize)
# {
#   "name":      "zaphod",
#   "age' :      27,
# }

touch arthur
# (zaphod has no shoesize)
# {
#   "name":      "arthur",
#   "age' :      20,
#   "shoesize":  15
# }

Create a design, and within it 3x views (queries)

cdbcli 

cd test_database
touch _design/shoeinfo

{
  "views": {

     /*
      * returns everything
		* ===================
		*/
     "all_docs"            : {
        "map" : "function(doc) {                      emit( doc.id, doc.shoesize );   }"
     }
 

     /*
      * checks for existence of doc.shoesize, emits only those docs
		* ===========================================================
		*/
     "docs_with_shoesizes" : {
	       "map" : "function(doc) {   if (doc.shoesize){ emit( doc.id, doc.shoesize ); } }"
	  }


     /*
      * ( returned documents are sorted by the first argument to emit     )
      * ( multiple fields can also be returned in a list, dict, or other  )
		* ===================================================================
      */
     "sorted_by_shoesize"  : {
	       "map" : "function(doc) {   if (doc.shoesize && doc.age){ emit( doc.shoesize, [doc.name,doc.age] ); } }"
	  }


  }
}

Query your view

curl -X GET http://127.0.0.1:5984/test_database/_design/showinfo/_view/all_docs
## function(doc) {  emit( doc.name, doc.shoesize );  }

{"total_rows":4,"offset":0,"rows":[
  {"id":"alex"   , "key":"alex"   , "value":8 },
  {"id":"arthur" , "key":"arthur" , "value":15},
  {"id":"will"   , "key":"will"   , "value":13},
  {"id":"zaphod" , "key":"zaphod" , "value":null} // zaphod's document is returned (with a shoesize of null , because the key does not exist)
]}

curl -X GET http://127.0.0.1:5984/test_database/_design/showinfo/_view/docs_with_shoesizes
## function(doc) {   if (doc.shoesize){ emit( doc.name, doc.shoesize ); } }

{"total_rows":3,"offset":0,"rows":[
  {"id":"alex"   , "key":"alex"   , "value":8 } ,
  {"id":"arthur" , "key":"arthur" , "value":15} ,
  {"id":"will"   , "key":"will"   , "value":13}
]}

curl -X GET http://127.0.0.1:5984/test_database/_design/showinfo/_view/sorted_by_shoesize
## function(doc) {   if (doc.shoesize && doc.age){ emit( doc.shoesize, [doc.name,doc.age] ); } }

{"total_rows":3,"offset":0,"rows":[
  {"id":"alex"   , "key":8  , "value":["alex"    , 26 ]} ,
  {"id":"will"   , "key":13 , "value":[ "will"   , 30 ]} ,
  {"id":"arthur" , "key":15 , "value":[ "arthur" , 35 ]}
]}