diff --git a/lib/etso/adapter/behaviour/schema.ex b/lib/etso/adapter/behaviour/schema.ex
index 498e071..f191ecf 100644
--- a/lib/etso/adapter/behaviour/schema.ex
+++ b/lib/etso/adapter/behaviour/schema.ex
@@ -13,8 +13,8 @@ defmodule Etso.Adapter.Behaviour.Schema do
   @impl Ecto.Adapter.Schema
   def insert_all(%{repo: repo}, %{schema: schema}, _, entries, _, _, _, _) do
     {:ok, ets_table} = TableRegistry.get_table(repo, schema)
-    ets_field_names = TableStructure.field_names(schema)
-    ets_changes = TableStructure.entries_to_tuples(ets_field_names, entries)
+    ets_field_sources = TableStructure.field_sources(schema)
+    ets_changes = TableStructure.entries_to_tuples(ets_field_sources, entries)
     ets_result = :ets.insert_new(ets_table, ets_changes)
     if ets_result, do: {length(ets_changes), nil}, else: {0, nil}
   end
@@ -22,8 +22,8 @@ defmodule Etso.Adapter.Behaviour.Schema do
   @impl Ecto.Adapter.Schema
   def insert(%{repo: repo}, %{schema: schema}, fields, _, _, _) do
     {:ok, ets_table} = TableRegistry.get_table(repo, schema)
-    ets_field_names = TableStructure.field_names(schema)
-    ets_changes = TableStructure.fields_to_tuple(ets_field_names, fields)
+    ets_field_sources = TableStructure.field_sources(schema)
+    ets_changes = TableStructure.fields_to_tuple(ets_field_sources, fields)
     ets_result = :ets.insert_new(ets_table, ets_changes)
     if ets_result, do: {:ok, []}, else: {:invalid, [unique: "primary_key"]}
   end
@@ -48,11 +48,11 @@ defmodule Etso.Adapter.Behaviour.Schema do
   end
 
   defp build_ets_updates(schema, fields) do
-    ets_field_names = TableStructure.field_names(schema)
+    ets_field_sources = TableStructure.field_sources(schema)
 
     for {field_name, field_value} <- fields do
       position_fun = fn x -> x == field_name end
-      position = 1 + Enum.find_index(ets_field_names, position_fun)
+      position = 1 + Enum.find_index(ets_field_sources, position_fun)
       {position, field_value}
     end
   end
diff --git a/lib/etso/ets/match_specification.ex b/lib/etso/ets/match_specification.ex
index aebe806..96cdea9 100644
--- a/lib/etso/ets/match_specification.ex
+++ b/lib/etso/ets/match_specification.ex
@@ -13,20 +13,20 @@ defmodule Etso.ETS.MatchSpecification do
 
   def build(query, params) do
     {_, schema} = query.from.source
-    field_names = Etso.ETS.TableStructure.field_names(schema)
-    match_head = build_head(field_names)
-    match_conditions = build_conditions(field_names, params, query)
-    match_body = [build_body(field_names, query)]
+    field_sources = Etso.ETS.TableStructure.field_sources(schema)
+    match_head = build_head(field_sources)
+    match_conditions = build_conditions(field_sources, params, query)
+    match_body = [build_body(field_sources, query)]
     {match_head, match_conditions, match_body}
   end
 
-  defp build_head(field_names) do
-    List.to_tuple(Enum.map(1..length(field_names), fn x -> :"$#{x}" end))
+  defp build_head(field_sources) do
+    List.to_tuple(Enum.map(1..length(field_sources), fn x -> :"$#{x}" end))
   end
 
-  defp build_conditions(field_names, params, %Ecto.Query{wheres: wheres}) do
+  defp build_conditions(field_sources, params, %Ecto.Query{wheres: wheres}) do
     Enum.reduce(wheres, [], fn %Ecto.Query.BooleanExpr{expr: expression}, acc ->
-      [build_condition(field_names, params, expression) | acc]
+      [build_condition(field_sources, params, expression) | acc]
     end)
   end
 
@@ -37,22 +37,22 @@ defmodule Etso.ETS.MatchSpecification do
   defmacrop guard_operator(operator), do: operator
 
   for operator <- ~w(== != < > <= >= and or)a do
-    defp build_condition(field_names, params, {unquote(operator), [], [lhs, rhs]}) do
-      lhs_condition = build_condition(field_names, params, lhs)
-      rhs_condition = build_condition(field_names, params, rhs)
+    defp build_condition(field_sources, params, {unquote(operator), [], [lhs, rhs]}) do
+      lhs_condition = build_condition(field_sources, params, lhs)
+      rhs_condition = build_condition(field_sources, params, rhs)
       {guard_operator(unquote(operator)), lhs_condition, rhs_condition}
     end
   end
 
   for operator <- ~w(not)a do
-    defp build_condition(field_names, params, {unquote(operator), [], [clause]}) do
-      condition = build_condition(field_names, params, clause)
+    defp build_condition(field_sources, params, {unquote(operator), [], [clause]}) do
+      condition = build_condition(field_sources, params, clause)
       {guard_operator(unquote(operator)), condition}
     end
   end
 
-  defp build_condition(field_names, params, {:in, [], [field, values]}) do
-    field_target = resolve_field_target(field_names, field)
+  defp build_condition(field_sources, params, {:in, [], [field, values]}) do
+    field_target = resolve_field_target(field_sources, field)
 
     case resolve_param_values(params, values) do
       [] -> []
@@ -60,16 +60,16 @@ defmodule Etso.ETS.MatchSpecification do
     end
   end
 
-  defp build_condition(field_names, params, {:is_nil, [], [field]}) do
-    {:==, build_condition(field_names, params, field), nil}
+  defp build_condition(field_sources, params, {:is_nil, [], [field]}) do
+    {:==, build_condition(field_sources, params, field), nil}
   end
 
   defp build_condition(_, params, {:^, [], [index]}) do
     Enum.at(params, index)
   end
 
-  defp build_condition(field_names, _params, field) when is_tuple(field) do
-    resolve_field_target(field_names, field)
+  defp build_condition(field_sources, _params, field) when is_tuple(field) do
+    resolve_field_target(field_sources, field)
   end
 
   defp build_condition(_, _, value) do
@@ -80,19 +80,19 @@ defmodule Etso.ETS.MatchSpecification do
     []
   end
 
-  defp build_body(field_names, %Ecto.Query{select: %{fields: fields}}) do
+  defp build_body(field_sources, %Ecto.Query{select: %{fields: fields}}) do
     for field <- fields do
-      resolve_field_target(field_names, field)
+      resolve_field_target(field_sources, field)
     end
   end
 
-  defp resolve_field_target(field_names, {:json_extract_path, [], [field, path]}) do
-    field_target = resolve_field_target(field_names, field)
+  defp resolve_field_target(field_sources, {:json_extract_path, [], [field, path]}) do
+    field_target = resolve_field_target(field_sources, field)
     resolve_field_target_path(field_target, path)
   end
 
-  defp resolve_field_target(field_names, {{:., _, [{:&, [], [0]}, field_name]}, [], []}) do
-    field_index = 1 + Enum.find_index(field_names, fn x -> x == field_name end)
+  defp resolve_field_target(field_sources, {{:., _, [{:&, [], [0]}, field_name]}, [], []}) do
+    field_index = 1 + Enum.find_index(field_sources, fn x -> x == field_name end)
     :"$#{field_index}"
   end
 
diff --git a/lib/etso/ets/table_structure.ex b/lib/etso/ets/table_structure.ex
index 1c3811c..b37720f 100644
--- a/lib/etso/ets/table_structure.ex
+++ b/lib/etso/ets/table_structure.ex
@@ -11,6 +11,12 @@ defmodule Etso.ETS.TableStructure do
     primary_key ++ (fields -- primary_key)
   end
 
+  def field_sources(schema) do
+    schema
+    |> field_names()
+    |> Enum.map(fn field -> schema.__schema__(:field_source, field) end)
+  end
+
   def fields_to_tuple(field_names, fields) do
     field_names
     |> Enum.map(&Keyword.get(fields, &1, nil))
diff --git a/test/northwind/repo_test.exs b/test/northwind/repo_test.exs
index 1a23291..3c22b14 100644
--- a/test/northwind/repo_test.exs
+++ b/test/northwind/repo_test.exs
@@ -182,7 +182,7 @@ defmodule Northwind.RepoTest do
 
   test "Delete Where" do
     query = Model.Employee |> where([e], e.employee_id in [1, 5])
-    assert [a, b] = Repo.all(query)
+    assert [_a, _b] = Repo.all(query)
     assert {2, nil} = Repo.delete_all(query)
     assert [] == Repo.all(query)
     refute [] == Repo.all(Model.Employee)
@@ -190,12 +190,12 @@ defmodule Northwind.RepoTest do
 
   test "Delete Where Select" do
     query = Model.Employee |> where([e], e.employee_id in [1, 5])
-    assert [a, b] = Repo.all(query)
+    assert [_a, _b] = Repo.all(query)
     assert {2, list} = Repo.delete_all(query |> select([e], {e, e.employee_id}))
     assert is_list(list)
     assert Enum.any?(list, &(elem(&1, 1) == 1))
     assert Enum.any?(list, &(elem(&1, 1) == 5))
-    assert [] = Repo.all(query)
+    assert [] == Repo.all(query)
     refute [] == Repo.all(Model.Employee)
   end
 
diff --git a/test/support/northwind/model/employee.ex b/test/support/northwind/model/employee.ex
index d05b51b..1cfe5a6 100644
--- a/test/support/northwind/model/employee.ex
+++ b/test/support/northwind/model/employee.ex
@@ -4,7 +4,7 @@ defmodule Northwind.Model.Employee do
 
   schema "employees" do
     # field :employee_id, :integer
-    field :reports_to, :integer
+    field :reports_to, :integer, source: :manager_id
     field :first_name, :string
     field :last_name, :string
     field :title, :string