Query DSL

Casbah provides a rich fluid query syntax, that allows you to construct DBObjects on the fly using MongoDB query operators.

Query Selectors

Comparison Operators

  • $all Matches arrays that contain all elements specified:

    "size" $all ("S", "M", "L")
    
  • $eq Matches values that are equal to the value specified:

    "price" $eq 10
    
  • $gt Matches values that are greater than the value specified in the query

  • $gte Matches values that are equal to or greater than the value specified:

    "price" $gt 10
    "price" $gte 10
    
  • $in Matches any of the values that exist in an array specified:

    "size" $in ("S", "M", "L")
    
  • $lt Matches values that are less than the value specified in the query

  • $lte Matches values that are less than or equal to the value specified:

    "price" $lt 100
    "price" $lte 100
    
  • $ne Matches all values that are not equal to the value specified:

    "price" $ne 1000
    
  • $nin Matches values that do not exist in an array specified:

    "size" $nin ("S", "XXL")
    

Logical Operators

  • $or Joins query clauses with a logical OR returns all documents that match the conditions of either clause:

    $or( "price" $lt 5 $gt 1, "promotion" $eq true )
    $or( ( "price" $lt 5 $gt 1 ) :: ( "stock" $gte 1 ) )
    
  • $and Joins query clauses with a logical AND returns all documents that match the conditions of both clauses:

    $and( "price" $lt 5 $gt 1, "stock" $gte 1 )
    $and( ( "price" $lt 5 $gt 1 ) :: ( "stock" $gte 1 ) )
    
  • $not Inverts the effect of a query expression and returns documents that do not match the query expression:

    "price" $not { _ $gte 5.1 }
    
  • $nor Joins query clauses with a logical NOR returns all documents that fail to match both clauses:

    $nor( "price" $eq 1.99 , "qty" $lt 20, "sale" $eq true )
    $nor( ( "price" $lt 5 $gt 1 ) :: ( "stock" $gte 1 ) )
    

Element Operators

  • $exists Matches documents that have the specified field:

    "qty" $exists true
    
  • $mod Performs a modulo operation on the value of a field and selects documents with a specified result:

    "qty" $mod (5, 0)
    
  • $type Selects documents if a field is of the specified type:

    "size".$type[BasicDBList]
    

JavaScript Operators

  • $where Matches documents that satisfy a JavaScript expression:

    $where("function () { this.credits == this.debits }")
    
  • $regex Selects documents where values match a specified regular expression. You can also use native regular expressions:

    "foo" $regex "^bar$"
    "foo" $eq "^bar$".r
    

Geospatial Operators

  • $geoWithin Selects geometries within a bounding GeoJSON geometry:

    // Create a GeoJson geometry document
    var geo = MongoDBObject("$geometry" ->
            MongoDBObject("$type" -> "polygon",
              "coordinates" -> (((GeoCoords(74.2332, -75.23452),
                                  GeoCoords(123, 456),
                                  GeoCoords(74.2332, -75.23452))))))
    
    
    // Example $geoWithin Queries
    "location" $geoWithin(geo)
    "location" $geoWithin $box ((74.2332, -75.23452), (123, 456))
    "location" $geoWithin $center ((50, 50), 10)
    "location" $geoWithin $centerSphere ((50, 50), 10)
    
  • $geoIntersects Selects geometries that intersect with a GeoJSON geometry:

    // Create a GeoJson geometry document
    var geo = MongoDBObject("$geometry" ->
                MongoDBObject("$type" -> "polygon",
                  "coordinates" -> (((GeoCoords(74.2332, -75.23452),
                                      GeoCoords(123, 456),
                                      GeoCoords(74.2332, -75.23452))))))
    val near = "location" $geoIntersects geo
    
  • $near Returns geospatial objects in proximity to a point:

    "location" $near (74.2332, -75.23452)
    
  • $nearSphere Returns geospatial objects in proximity to a point on a sphere:

    "location" $nearSphere (74.2332, -75.23452)
    

Array Query Operators

  • $elemMatch Selects documents if element in the array field matches all the specified $elemMatch conditions:

    "colour" $elemMatch MongoDBObject("base" -> "red", "flash" -> "silver")
    
  • $size Selects documents if the array field is a specified size:

    "comments" $size 12
    

Update DSL Operators

Field Operators

  • $inc Increments the value of the field by the specified amount:

    $inc("sold" -> 1, "stock" -> -1)
    
  • $rename Renames a field:

    $rename("color" -> "colour", "realize" -> "realise")
    
  • $setOnInsert Sets the value of a field upon documentation creation during an upsert. Has no effect on update operations that modify existing documents:

    $setOnInsert("promotion" -> "new")
    
  • $set Sets the value of a field in an existing document:

    $set("promotion" -> "sale", "qty" -> 100)
    
  • $unset Removes the specified field from an existing document:

    $unset("promotion")
    
  • $currentDate Updates the specified fields to current server-side date or timestamp (the only allowed values):

    $currentDate("lastUpdated" -> "date", "ts" -> "timestamp")
    

Array Update Operators

  • $addToSet Adds elements to an existing array only if they do not already exist in the set:

    $addToSet("sizes" -> "L", "colours" -> "Blue")
    $addToSet("sizes") $each ("S", "M", "L", "XL")
    
  • $pop Removes the first or last item of an array:

    $pop("sizes" -> "L")
    
  • $pull Removes items from an array that match a query statement:

    $pull("sizes" -> "L")
    $pull("widgets" $gt 2 )
    
  • $pullAll Removes multiple values from an array:

    $pullAll("sizes" -> ("S", "XL"))
    
  • $push Adds an item to an array:

    $push("sizes" -> "L")
    $push("widgets" $gt 2 )
    $push("sizes") $each ("S", "M", "L", "XL")
    
  • $pushAll Deprecated. Adds several items to an array:

    $pushAll("sizes" -> ("S", "XL"))
    

Bitwise Operators

  • $bit Performs bitwise AND and OR updates of integer values:

    $bit("foo") and 5
    

For the full query syntax to MongoDB see the core docs at: docs.mongodb.org