Separate as() and into()

Author: xitology

src/FunSQL.jl

@@ -55,6 +55,7 @@ export
     funsql_group,
     funsql_highlight,
     funsql_in,
+    funsql_into,
     funsql_iterate,
     funsql_is_not_null,
     funsql_is_null,

src/link.jl

@@ -114,19 +114,15 @@ function dismantle(n::GroupNode, ctx)
     Group(over = over′, by = by′, sets = n.sets, name = n.name, label_map = n.label_map)
 end
 
-function dismantle(n::IterateNode, ctx)
+function dismantle(n::IntoNode, ctx)
     over′ = dismantle(n.over, ctx)
-    iterator′ = dismantle(n.iterator, ctx)
-    Iterate(over = over′, iterator = iterator′)
+    Into(over = over′, name = n.name)
 end
 
-function dismantle(n::JoinNode, ctx)
-    rt = row_type(n.joinee)
-    router = JoinRouter(Set(keys(rt.fields)), !isa(rt.group, EmptyType))
+function dismantle(n::IterateNode, ctx)
     over′ = dismantle(n.over, ctx)
-    joinee′ = dismantle(n.joinee, ctx)
-    on′ = dismantle_scalar(n.on, ctx)
-    RoutedJoin(over = over′, joinee = joinee′, on = on′, router = router, left = n.left, right = n.right, optional = n.optional)
+    iterator′ = dismantle(n.iterator, ctx)
+    Iterate(over = over′, iterator = iterator′)
 end
 
 function dismantle(n::LimitNode, ctx)
@@ -172,6 +168,13 @@ function dismantle_scalar(n::ResolvedNode, ctx)
     end
 end
 
+function dismantle(n::RoutedJoinNode, ctx)
+    over′ = dismantle(n.over, ctx)
+    joinee′ = dismantle(n.joinee, ctx)
+    on′ = dismantle_scalar(n.on, ctx)
+    RoutedJoin(over = over′, joinee = joinee′, on = on′, name = n.name, left = n.left, right = n.right, optional = n.optional)
+end
+
 function dismantle(n::SelectNode, ctx)
     over′ = dismantle(n.over, ctx)
     args′ = dismantle_scalar(n.args, ctx)
@@ -219,16 +222,7 @@ function link(n::AppendNode, ctx)
 end
 
 function link(n::AsNode, ctx)
-    refs = SQLNode[]
-    for ref in ctx.refs
-        if @dissect(ref, over |> Nested(name = name))
-            @assert name == n.name
-            push!(refs, over)
-        else
-            error()
-        end
-    end
-    over′ = link(n.over, ctx, refs)
+    over′ = link(n.over, ctx)
     As(over = over′, name = n.name)
 end
 
@@ -276,10 +270,8 @@ function link(n::FromIterateNode, ctx)
 end
 
 function link(n::FromTableExpressionNode, ctx)
-    refs = ctx.cte_refs[(n.name, n.depth)]
-    for ref in ctx.refs
-        push!(refs, Nested(over = ref, name = n.name))
-    end
+    cte_refs = ctx.cte_refs[(n.name, n.depth)]
+    append!(cte_refs, ctx.refs)
     n
 end
 
@@ -320,6 +312,20 @@ function link(n::GroupNode, ctx)
     Group(over = over′, by = n.by, sets = n.sets, name = n.name, label_map = n.label_map)
 end
 
+function link(n::IntoNode, ctx)
+    refs = SQLNode[]
+    for ref in ctx.refs
+        if @dissect(ref, over |> Nested(name = name))
+            @assert name == n.name
+            push!(refs, over)
+        else
+            error()
+        end
+    end
+    over′ = link(n.over, ctx, refs)
+    Into(over = over′, name = n.name)
+end
+
 function link(n::IterateNode, ctx)
     iterator′ = n.iterator
     defs = copy(ctx.defs)
@@ -351,53 +357,6 @@ function link(n::IterateNode, ctx)
     Padding(over = n′)
 end
 
-function route(r::JoinRouter, ref::SQLNode)
-    if @dissect(ref, over |> Nested(name = name)) && name in r.label_set
-        return 1
-    end
-    if @dissect(ref, Get(name = name)) && name in r.label_set
-        return 1
-    end
-    if @dissect(ref, over |> Agg()) && r.group
-        return 1
-    end
-    return -1
-end
-
-function link(n::RoutedJoinNode, ctx)
-    lrefs = SQLNode[]
-    rrefs = SQLNode[]
-    for ref in ctx.refs
-        turn = route(n.router, ref)
-        push!(turn < 0 ? lrefs : rrefs, ref)
-    end
-    if n.optional && isempty(rrefs)
-        return link(n.over, ctx)
-    end
-    ln_ext_refs = length(lrefs)
-    rn_ext_refs = length(rrefs)
-    refs′ = SQLNode[]
-    lateral_refs = SQLNode[]
-    gather!(n.joinee, ctx, lateral_refs)
-    append!(lrefs, lateral_refs)
-    lateral = !isempty(lateral_refs)
-    gather!(n.on, ctx, refs′)
-    for ref in refs′
-        turn = route(n.router, ref)
-        push!(turn < 0 ? lrefs : rrefs, ref)
-    end
-    over′ = Linked(lrefs, ln_ext_refs, over = link(n.over, ctx, lrefs))
-    joinee′ = Linked(rrefs, rn_ext_refs, over = link(n.joinee, ctx, rrefs))
-    RoutedJoinNode(
-        over = over′,
-        joinee = joinee′,
-        on = n.on,
-        router = n.router,
-        left = n.left,
-        right = n.right,
-        lateral = lateral)
-end
-
 function link(n::LimitNode, ctx)
     over′ = Linked(ctx.refs, over = link(n.over, ctx))
     Limit(over = over′, offset = n.offset, limit = n.limit)
@@ -446,6 +405,46 @@ function link(n::PartitionNode, ctx)
     Partition(over = over′, by = n.by, order_by = n.order_by, frame = n.frame, name = n.name)
 end
 
+function link(n::RoutedJoinNode, ctx)
+    lrefs = SQLNode[]
+    rrefs = SQLNode[]
+    for ref in ctx.refs
+        if @dissect(ref, over |> Nested(name = name)) && name === n.name
+            push!(rrefs, ref)
+        else
+            push!(lrefs, ref)
+        end
+    end
+    if n.optional && isempty(rrefs)
+        return link(n.over, ctx)
+    end
+    ln_ext_refs = length(lrefs)
+    rn_ext_refs = length(rrefs)
+    refs′ = SQLNode[]
+    lateral_refs = SQLNode[]
+    gather!(n.joinee, ctx, lateral_refs)
+    append!(lrefs, lateral_refs)
+    lateral = !isempty(lateral_refs)
+    gather!(n.on, ctx, refs′)
+    for ref in refs′
+        if @dissect(ref, over |> Nested(name = name)) && name === n.name
+            push!(rrefs, ref)
+        else
+            push!(lrefs, ref)
+        end
+    end
+    over′ = Linked(lrefs, ln_ext_refs, over = link(n.over, ctx, lrefs))
+    joinee′ = Linked(rrefs, rn_ext_refs, over = link(Into(over = n.joinee, name = n.name), ctx, rrefs))
+    RoutedJoinNode(
+        over = over′,
+        joinee = joinee′,
+        on = n.on,
+        name = n.name,
+        left = n.left,
+        right = n.right,
+        lateral = lateral)
+end
+
 function link(n::SelectNode, ctx)
     refs = SQLNode[]
     gather!(n.args, ctx, refs)

src/nodes.jl

@@ -696,6 +696,7 @@ include("nodes/get.jl")
 include("nodes/group.jl")
 include("nodes/highlight.jl")
 include("nodes/internal.jl")
+include("nodes/into.jl")
 include("nodes/iterate.jl")
 include("nodes/join.jl")
 include("nodes/limit.jl")

src/nodes/as.jl

@@ -18,8 +18,7 @@ AsNode(name; over = nothing) =
     As(name; over = nothing)
     name => over
 
-In a scalar context, `As` specifies the name of the output column.  When
-applied to tabular data, `As` wraps the data in a nested record.
+`As` specifies the name of the output column.
 
 The arrow operator (`=>`) is a shorthand notation for `As`.
 
@@ -37,19 +36,19 @@ SELECT "person_1"."person_id" AS "id"
 FROM "person" AS "person_1"
 ```
 
-*Show all patients together with their state of residence.*
+*Show all patients together with their primary care provider.*
 
 ```jldoctest
-julia> person = SQLTable(:person, columns = [:person_id, :year_of_birth, :location_id]);
+julia> person = SQLTable(:person, columns = [:person_id, :year_of_birth, :provider_id]);
 
-julia> location = SQLTable(:location, columns = [:location_id, :state]);
+julia> provider = SQLTable(:provider, columns = [:provider_id, :provider_name]);
 
 julia> q = From(:person) |>
-           Join(From(:location) |> As(:location),
-                on = Get.location_id .== Get.location.location_id) |>
-           Select(Get.person_id, Get.location.state);
+           Join(From(:provider) |> As(:pcp),
+                on = Get.provider_id .== Get.pcp.provider_id) |>
+           Select(Get.person_id, Get.pcp.provider_name);
 
-julia> print(render(q, tables = [person, location]))
+julia> print(render(q, tables = [person, provider]))
 SELECT
   "person_1"."person_id",
   "location_1"."state"

src/nodes/internal.jl

@@ -202,30 +202,22 @@ PrettyPrinting.quoteof(n::FromFunctionNode, ctx::QuoteContext) =
          Expr(:kw, :columns, Expr(:vect, [QuoteNode(col) for col in n.columns]...)))
 
 # Annotated Join node.
-struct JoinRouter
-    label_set::Set{Symbol}
-    group::Bool
-end
-
-PrettyPrinting.quoteof(r::JoinRouter) =
-    Expr(:call, nameof(JoinRouter), quoteof(r.label_set), quoteof(r.group))
-
 mutable struct RoutedJoinNode <: TabularNode
     over::Union{SQLNode, Nothing}
     joinee::SQLNode
     on::SQLNode
-    router::JoinRouter
+    name::Symbol
     left::Bool
     right::Bool
     lateral::Bool
     optional::Bool
 
-    RoutedJoinNode(; over, joinee, on, router, left, right, lateral = false, optional = false) =
-        new(over, joinee, on, router, left, right, lateral, optional)
+    RoutedJoinNode(; over, joinee, on, name = label(joinee), left, right, lateral = false, optional = false) =
+        new(over, joinee, on, name, left, right, lateral, optional)
 end
 
-RoutedJoinNode(joinee, on; over = nothing, router, left = false, right = false, lateral = false, optional = false) =
-    RoutedJoinNode(over = over, joinee = joinee, on = on, router, left = left, right = right, lateral = lateral, optional = optional)
+RoutedJoinNode(joinee, on; over = nothing, name = label(joinee), left = false, right = false, lateral = false, optional = false) =
+    RoutedJoinNode(over = over, name = name, on = on, router, left = left, right = right, lateral = lateral, optional = optional)
 
 RoutedJoin(args...; kws...) =
     RoutedJoinNode(args...; kws...) |> SQLNode
@@ -235,7 +227,7 @@ function PrettyPrinting.quoteof(n::RoutedJoinNode, ctx::QuoteContext)
     if !ctx.limit
         push!(ex.args, quoteof(n.joinee, ctx))
         push!(ex.args, quoteof(n.on, ctx))
-        push!(ex.args, Expr(:kw, :router, quoteof(n.router)))
+        push!(ex.args, Expr(:kw, :name, QuoteNode(n.name)))
         if n.left
             push!(ex.args, Expr(:kw, :left, n.left))
         end

src/nodes/into.jl

@@ -0,0 +1,39 @@
+# Wrap the output into a nested record.
+
+mutable struct IntoNode <: TabularNode
+    over::Union{SQLNode, Nothing}
+    name::Symbol
+
+    IntoNode(;
+           over = nothing,
+           name::Union{Symbol, AbstractString}) =
+        new(over, Symbol(name))
+end
+
+IntoNode(name; over = nothing) =
+    IntoNode(over = over, name = name)
+
+"""
+    Into(; over = nothing, name)
+    Into(name; over = nothing)
+
+`Into` wraps output columns in a nested record.
+"""
+Into(args...; kws...) =
+    IntoNode(args...; kws...) |> SQLNode
+
+const funsql_into = Into
+
+dissect(scr::Symbol, ::typeof(Into), pats::Vector{Any}) =
+    dissect(scr, IntoNode, pats)
+
+function PrettyPrinting.quoteof(n::IntoNode, ctx::QuoteContext)
+    ex = Expr(:call, nameof(Into), quoteof(n.name))
+    if n.over !== nothing
+        ex = Expr(:call, :|>, quoteof(n.over, ctx), ex)
+    end
+    ex
+end
+
+label(n::IntoNode) =
+    n.name

src/resolve.jl

@@ -160,9 +160,8 @@ end
 
 function resolve(n::AsNode, ctx)
     over′ = resolve(n.over, ctx)
-    t = row_type(over′)
     n′ = As(name = n.name, over = over′)
-    Resolved(RowType(FieldTypeMap(n.name => t)), over = n′)
+    Resolved(type(over′), over = n′)
 end
 
 function resolve_scalar(n::AsNode, ctx)
@@ -357,6 +356,13 @@ resolve(n::HighlightNode, ctx) =
 resolve_scalar(n::HighlightNode, ctx) =
     resolve_scalar(n.over, ctx)
 
+function resolve(n::IntoNode, ctx)
+    over′ = resolve(n.over, ctx)
+    t = row_type(over′)
+    n′ = Into(name = n.name, over = over′)
+    Resolved(RowType(FieldTypeMap(n.name => t)), over = n′)
+end
+
 function resolve(n::IterateNode, ctx)
     over′ = resolve(n.over, ResolveContext(ctx, knot_type = nothing, implicit_knot = false))
     t = row_type(over′)
@@ -374,21 +380,18 @@ end
 function resolve(n::JoinNode, ctx)
     over′ = resolve(n.over, ctx)
     lt = row_type(over′)
+    name = label(n.joinee)
     joinee′ = resolve(n.joinee, ResolveContext(ctx, row_type = lt, implicit_knot = false))
     rt = row_type(joinee′)
     fields = FieldTypeMap()
     for (f, ft) in lt.fields
-        fields[f] = get(rt.fields, f, ft)
+        fields[f] = ft
     end
-    for (f, ft) in rt.fields
-        if !haskey(fields, f)
-            fields[f] = ft
-        end
-    end
-    group = rt.group isa EmptyType ? lt.group : rt.group
+    fields[name] = rt
+    group = lt.group
     t = RowType(fields, group)
     on′ = resolve_scalar(n.on, ctx, t)
-    n′ = Join(over = over′, joinee = joinee′, on = on′, left = n.left, right = n.right, optional = n.optional)
+    n′ = RoutedJoin(over = over′, joinee = joinee′, on = on′, name = name, left = n.left, right = n.right, optional = n.optional)
     Resolved(t, over = n′)
 end
 
@@ -491,16 +494,7 @@ function resolve(n::Union{WithNode, WithExternalNode}, ctx)
         v = get(ctx.cte_types, name, nothing)
         depth = 1 + (v !== nothing ? v[1] : 0)
         t = row_type(args′[i])
-        cte_t = get(t.fields, name, EmptyType())
-        if !(cte_t isa RowType)
-            throw(
-                ReferenceError(
-                    REFERENCE_ERROR_TYPE.INVALID_TABLE_REFERENCE,
-                    name = name,
-                    path = get_path(ctx)))
-
-        end
-        cte_types′ = Base.ImmutableDict(cte_types′, name => (depth, cte_t))
+        cte_types′ = Base.ImmutableDict(cte_types′, name => (depth, t))
     end
     ctx′ = ResolveContext(ctx, cte_types = cte_types′)
     over′ = resolve(n.over, ctx′)