ArangoDB: Remove by example

'collection.removeByExample(example)' method is used to remove documents by example.

 

Signature

collection.removeByExample(example)

collection.removeByExample(document, waitForSync)

collection.removeByExample(document, waitForSync, limit)

 

If you set ‘waitForSync’ parameter to true, then ArangoDB enables the operation to be in force sync with disk. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied.

 

‘limit’ parameter is used to limit number of removals.

 

Let’s experiment with an example.

127.0.0.1:8529@abc_org> db.user.toArray()
[ 
  { 
    "_key" : "17095", 
    "_id" : "user/17095", 
    "_rev" : "_cRe1H-6---", 
    "id" : 4, 
    "firstName" : "Venkat", 
    "lastName" : "Ptr", 
    "age" : 35 
  }, 
  { 
    "_key" : "23404", 
    "_id" : "user/23404", 
    "_rev" : "_cRhMFQ6---", 
    "id" : 5, 
    "firstName" : "Gireesh", 
    "lastName" : "Amara", 
    "age" : 30 
  }, 
  { 
    "_key" : "31893", 
    "_id" : "user/31893", 
    "_rev" : "_cR9QHBy---", 
    "firstName" : "Shanmuk", 
    "lastName" : "Rao", 
    "age" : 33, 
    "id" : 6 
  }, 
  { 
    "_key" : "31916", 
    "_id" : "user/31916", 
    "_rev" : "_cR9Qdi2---", 
    "firstName" : "Jaideep", 
    "lastName" : "Gera", 
    "age" : 35, 
    "id" : 7 
  }, 
  { 
    "_key" : "31930", 
    "_id" : "user/31930", 
    "_rev" : "_cR9QxTy---", 
    "firstName" : "Sailu", 
    "lastName" : "PTR", 
    "age" : 36, 
    "id" : 8 
  }, 
  { 
    "_key" : "31944", 
    "_id" : "user/31944", 
    "_rev" : "_cR9RJMy---", 
    "firstName" : "Chamu", 
    "lastName" : "M", 
    "age" : 33, 
    "id" : 9 
  }, 
  { 
    "_key" : "31958", 
    "_id" : "user/31958", 
    "_rev" : "_cR9RbtC---", 
    "firstName" : "Ravi", 
    "lastName" : "Chandra", 
    "age" : 35, 
    "id" : 10 
  } 
]

 

As you see above snippet, user collection has 3 documents with the age 35.

 

Let’s delete any 2 documents with age 35.

db.user.removeByExample({"age": 35}, false, 2)

127.0.0.1:8529@abc_org> db.user.removeByExample({"age": 35}, false, 2)
2

127.0.0.1:8529@abc_org> db.user.toArray()
[ 
  { 
    "_key" : "23404", 
    "_id" : "user/23404", 
    "_rev" : "_cRhMFQ6---", 
    "id" : 5, 
    "firstName" : "Gireesh", 
    "lastName" : "Amara", 
    "age" : 30 
  }, 
  { 
    "_key" : "31893", 
    "_id" : "user/31893", 
    "_rev" : "_cR9QHBy---", 
    "firstName" : "Shanmuk", 
    "lastName" : "Rao", 
    "age" : 33, 
    "id" : 6 
  }, 
  { 
    "_key" : "31930", 
    "_id" : "user/31930", 
    "_rev" : "_cR9QxTy---", 
    "firstName" : "Sailu", 
    "lastName" : "PTR", 
    "age" : 36, 
    "id" : 8 
  }, 
  { 
    "_key" : "31944", 
    "_id" : "user/31944", 
    "_rev" : "_cR9RJMy---", 
    "firstName" : "Chamu", 
    "lastName" : "M", 
    "age" : 33, 
    "id" : 9 
  }, 
  { 
    "_key" : "31958", 
    "_id" : "user/31958", 
    "_rev" : "_cR9RbtC---", 
    "firstName" : "Ravi", 
    "lastName" : "Chandra", 
    "age" : 35, 
    "id" : 10 
  } 
]

 

 

 

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