polydb:method find_one in the database

src/polydb.jl

@@ -7,7 +7,7 @@
 
 import Mongoc
 
-import Mongoc: find
+import Mongoc: find, find_one
 
 #Polymake.Polydb's types store information via
 # a corresponding Mongoc type variable
@@ -123,6 +123,7 @@
 function Base.length(c::Collection{T}, d::Pair...) where T
  return Base.length(c.mcol, Mongoc.BSON(d...))
 end
+
 """
  find(c::Collection{T}, d::Dict=Dict(); opts::Union{Nothing, Dict})
 
@@ -166,6 +167,79 @@
  return Cursor{T}(Mongoc.find(c.mcol, Mongoc.BSON(d...)))
 end
 
+"""
+ find_one(c::Collection{T}, d::Dict=Dict(); opts::Union{Nothing, Dict})
+
+Return one document from a collection `c` matching the criteria given by `d`.
+`T` can be chosen from `Polymake.BigObject` and `Mongoc.BSON`.
+Apply search options `opts`.
+# Examples
+```julia-repl
+julia> db = Polymake.Polydb.get_db();
+
+julia> collection = db["Polytopes.Lattice.SmoothReflexive"];
+
+julia> query = Dict("DIM"=>5, "N_FACETS"=>8);
+
+julia> opts = Dict("skip"=>13);
+
+julia> pm_object = Polymake.Polydb.find_one(collection, query, opts=opts);
+
+julia> typeof(pm_object)
+Polymake.LibPolymake.BigObjectAllocated
+
+julia> collection_bson = Polymake.Polydb.Collection{Mongoc.BSON}(collection);
+
+julia> pm_object = Polymake.Polydb.find_one(collection_bson, query, opts=opts);
+
+julia> typeof(pm_object)
+Mongoc.BSON
+```
+"""
+function Mongoc.find_one(c::Collection{Polymake.BigObject}, d::Dict=Dict(); opts::Union{Nothing, Dict}=nothing)
+ p = Mongoc.find_one(c.mcol, Mongoc.BSON(d); options=(isnothing(opts) ? nothing : Mongoc.BSON(opts)))
+ return isnothing(p) ? nothing : parse_document(p)
+end
+
+function Mongoc.find_one(c::Collection{Mongoc.BSON}, d::Dict=Dict(); opts::Union{Nothing, Dict}=nothing)
+ p = Mongoc.find_one(c.mcol, Mongoc.BSON(d); options=(isnothing(opts) ? nothing : Mongoc.BSON(opts)))
+ return isnothing(p) ? nothing : p
+end
+
+"""
+ find_one(c::Collection{T}, d::Pair...)
+
+Return one document from a collection `c` matching the criteria given by `d`.
+`T` can be chosen from `Polymake.BigObject` and `Mongoc.BSON`.
+# Examples
+```julia-repl
+julia> db = Polymake.Polydb.get_db();
+
+julia> collection = db["Polytopes.Lattice.SmoothReflexive"];
+
+julia> pm_object = Polymake.Polydb.find_one(collection, "DIM"=>3, "N_FACETS"=>5);
+
+julia> typeof(pm_object)
+Polymake.LibPolymake.BigObjectAllocated
+
+julia> collection_bson = Polymake.Polydb.Collection{Mongoc.BSON}(collection);
+
+julia> pm_object = Polymake.Polydb.find_one(collection_bson, "DIM"=>3, "N_FACETS"=>5);
+
+julia> typeof(pm_object)
+Mongoc.BSON
+```
+"""
+function Mongoc.find_one(c::Collection{Polymake.BigObject}, d::Pair...)
+ p = Mongoc.find_one(c.mcol, Mongoc.BSON(d...))
+ return isnothing(p) ? nothing : parse_document(p)
+end
+
+function Mongoc.find_one(c::Collection{Mongoc.BSON}, d::Pair...)
+ p = Mongoc.find_one(c.mcol, Mongoc.BSON(d...))
+ return isnothing(p) ? nothing : p
+end
+
 """
  Collection{T}(c::Collection)
 

test/polydb.jl

@@ -30,6 +30,8 @@ using Polymake.Polydb.Mongoc
  @test Polymake.Polydb.Collection{Polymake.BigObject}(collection_bson) isa Polymake.Polydb.Collection{Polymake.BigObject}
  constraints = _acp(["DIM" => 3, "N_VERTICES" => 8])
  query = Dict(constraints...)
+ opts_success = Dict("skip"=>3)
+ opts_nothing = Dict("skip"=>13)
  # Queries
  @test Polymake.Polydb.find(collection_bo, query) isa Polymake.Polydb.Cursor
  @test Polymake.Polydb.find(collection_bo, query) isa Polymake.Polydb.Cursor{Polymake.BigObject}
@@ -46,6 +48,16 @@ using Polymake.Polydb.Mongoc
  @test Polymake.Polydb.Cursor{Polymake.BigObject}(results_bson) isa Polymake.Polydb.Cursor
  @test Polymake.Polydb.Cursor{Polymake.BigObject}(results_bson) isa Polymake.Polydb.Cursor{Polymake.BigObject}
 
+ @test Polymake.Polydb.find_one(collection_bo, query) isa Polymake.BigObject
+ @test Polymake.Polydb.find_one(collection_bo, query, opts=opts_success) isa Polymake.BigObject
+ @test isnothing(Polymake.Polydb.find_one(collection_bo, query, opts=opts_nothing))
+ @test Polymake.Polydb.find_one(collection_bo, constraints...) isa Polymake.BigObject
+
+ @test Polymake.Polydb.find_one(collection_bson, query) isa Mongoc.BSON
+ @test Polymake.Polydb.find_one(collection_bson, query, opts=opts_success) isa Mongoc.BSON
+ @test isnothing(Polymake.Polydb.find_one(collection_bson, query, opts=opts_nothing))
+ @test Polymake.Polydb.find_one(collection_bson, constraints...) isa Mongoc.BSON
+
  @test length(collection_bo, constraints...) == 7
  @test length(collection_bo, query) == 7
  @test length(collection_bson, constraints...) == 7