Full-joins in SQLite (#6215)

Closes #5254

In #6189 the SQLite version was bumped to a newer release which has builtin support for Full and Right joins, so no workaround is no longer needed.

distribution/lib/Standard/Database/0.0.0-dev/src/Data/Dialect.enso

@@ -61,14 +61,6 @@ type Dialect
         _ = [internal_column, sort_direction, text_ordering]
         Unimplemented.throw "This is an interface only."
 
-    ## PRIVATE
-       Prepares a join operation, returning a new table instance encapsulating a
-       proper query.
-    prepare_join : Connection -> Join_Kind -> Text -> From_Spec -> From_Spec -> Vector -> Vector -> Vector -> Table
-    prepare_join self connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select =
-        _ = [connection, join_kind, new_table_name, left_subquery, right_subquery, on_expressions, where_expressions, columns_to_select]
-        Unimplemented.throw "This is an interface only."
-
     ## PRIVATE
        Prepares a distinct operation.
     prepare_distinct : Table -> Vector -> Case_Sensitivity -> Problem_Builder -> Table

distribution/lib/Standard/Database/0.0.0-dev/src/Data/Table.enso

@@ -952,7 +952,9 @@ type Table
                 Join_Kind.Right_Exclusive -> SQL_Join_Kind.Right
 
             problem_builder.attach_problems_before on_problems <|
-                self.connection.dialect.prepare_join self.connection sql_join_kind new_table_name left_setup.subquery right_setup.subquery on_expressions where_expressions columns_to_select=result_columns
+                new_from = From_Spec.Join sql_join_kind left_setup.subquery right_setup.subquery on_expressions
+                new_ctx = Context.for_subquery new_from . set_where_filters where_expressions
+                Table.Value new_table_name self.connection result_columns new_ctx
 
     ## ALIAS Cartesian Join
        Joins tables by pairing every row of the left table with every row of the

distribution/lib/Standard/Database/0.0.0-dev/src/Internal/Common/Database_Join_Helper.enso

@@ -15,12 +15,6 @@ import project.Internal.IR.Internal_Column.Internal_Column
 import project.Internal.IR.SQL_Expression.SQL_Expression
 import project.Internal.SQL_Type_Reference.SQL_Type_Reference
 
-## PRIVATE
-default_prepare_join connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select =
-    new_from = From_Spec.Join join_kind left_subquery right_subquery on_expressions
-    new_ctx = Context.for_subquery new_from . set_where_filters where_expressions
-    Table.Value new_table_name connection columns_to_select new_ctx
-
 ## PRIVATE
 make_join_helpers left_table right_table left_column_mapping right_column_mapping =
     ## Resolves the column in the original table and finds the expression

distribution/lib/Standard/Database/0.0.0-dev/src/Internal/Postgres/Postgres_Dialect.enso

@@ -80,13 +80,6 @@ type Postgres_Dialect
     prepare_order_descriptor self internal_column sort_direction text_ordering =
         make_order_descriptor internal_column sort_direction text_ordering
 
-    ## PRIVATE
-       Prepares a join operation, returning a new table instance encapsulating a
-       proper query.
-    prepare_join : Connection -> SQL_Join_Kind -> Text -> From_Spec -> From_Spec -> Vector -> Vector -> Vector -> Table
-    prepare_join self connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select =
-        Database_Join_Helper.default_prepare_join connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select
-
     ## PRIVATE
        Prepares a distinct operation.
     prepare_distinct : Table -> Vector -> Case_Sensitivity -> Problem_Builder -> Table

distribution/lib/Standard/Database/0.0.0-dev/src/Internal/Redshift/Redshift_Dialect.enso

@@ -73,13 +73,6 @@ type Redshift_Dialect
     prepare_order_descriptor self internal_column sort_direction text_ordering =
         Postgres_Dialect.make_order_descriptor internal_column sort_direction text_ordering
 
-    ## PRIVATE
-       Prepares a join operation, returning a new table instance encapsulating a
-       proper query.
-    prepare_join : Connection -> SQL_Join_Kind -> Text -> From_Spec -> From_Spec -> Vector -> Vector -> Vector -> Table
-    prepare_join self connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select =
-        Database_Join_Helper.default_prepare_join connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select
-
     ## PRIVATE
        A heuristic used by `Connection.query` to determine if a given text looks
        like a SQL query for the given dialect or is rather a table name.

distribution/lib/Standard/Database/0.0.0-dev/src/Internal/SQLite/SQLite_Dialect.enso

@@ -90,22 +90,6 @@ type SQLite_Dialect
                         True ->
                             Order_Descriptor.Value internal_column.expression sort_direction collation="NOCASE"
 
-    ## PRIVATE
-       Prepares a join operation, returning a new table instance encapsulating a
-       proper query.
-    prepare_join : Connection -> SQL_Join_Kind -> Text -> From_Spec -> From_Spec -> Vector -> Vector -> Vector -> Table
-    prepare_join self connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select = case join_kind of
-        SQL_Join_Kind.Right ->
-            # We just do a left join with swapped order of sub-queries, while keeping the original order of columns.
-            Database_Join_Helper.default_prepare_join connection SQL_Join_Kind.Left new_table_name right_subquery left_subquery on_expressions where_expressions columns_to_select
-        SQL_Join_Kind.Full ->
-            ## TODO workaround for full joins by left outer + right-anti union
-               https://www.pivotaltracker.com/story/show/184090548
-            Error.throw (Unsupported_Database_Operation.Error "Full outer joins are not YET supported by the SQLite backend. You may need to materialize the Table to perform this operation.")
-        _ ->
-            # Other kinds of joins just fall back to the default logic.
-            Database_Join_Helper.default_prepare_join connection join_kind new_table_name left_subquery right_subquery on_expressions where_expressions columns_to_select
-
     ## PRIVATE
        Prepares a distinct operation.
     prepare_distinct : Table -> Vector -> Case_Sensitivity -> Problem_Builder -> Table

test/Table_Tests/src/Common_Table_Operations/Join/Join_Spec.enso

@@ -46,16 +46,11 @@ spec setup =
 
         Test.specify "should allow Full join" <|
             t3 = t1.join t2 join_kind=Join_Kind.Full |> materialize |> _.order_by ["X", "W"]
-            case setup.test_selection.supports_full_join of
-                True ->
-                    expect_column_names ["X", "Y", "Z", "W"] t3
-                    t3.at "X" . to_vector . should_equal [Nothing, 1, 2, 2, 3]
-                    t3.at "Y" . to_vector . should_equal [Nothing, 4, 5, 5, 6]
-                    t3.at "Z" . to_vector . should_equal [4, Nothing, 2, 2, 3]
-                    t3.at "W" . to_vector . should_equal [7, Nothing, 4, 6, 5]
-                False ->
-                    t3.should_fail_with Unsupported_Database_Operation
-
+            expect_column_names ["X", "Y", "Z", "W"] t3
+            t3.at "X" . to_vector . should_equal [Nothing, 1, 2, 2, 3]
+            t3.at "Y" . to_vector . should_equal [Nothing, 4, 5, 5, 6]
+            t3.at "Z" . to_vector . should_equal [4, Nothing, 2, 2, 3]
+            t3.at "W" . to_vector . should_equal [7, Nothing, 4, 6, 5]
 
         Test.specify "should allow Left Outer join" <|
             t4 = t1.join t2 join_kind=Join_Kind.Left_Outer |> materialize |> _.order_by ["X", "W"]
@@ -263,17 +258,14 @@ spec setup =
             t2.at "Right_A" . to_vector . should_equal ["B", "C", "C", "D"]
 
             t3 = t1.join t1 join_kind=Join_Kind.Full on=(Join_Condition.Equals left="X" right="Y") |> materialize |> _.order_by ["X", "Y", "Right_X"]
-            case setup.test_selection.supports_full_join of
-                True ->
-                    expect_column_names ["X", "Y", "A", "Right_X", "Right_Y", "Right_A"] t3
-                    t3.at "X" . to_vector . should_equal [Nothing, Nothing, 0, 1, 2, 2, 3]
-                    t3.at "Right_Y" . to_vector . should_equal [100, 4, Nothing, 1, 2, 2, 3]
-
-                    t3.at "Y" . to_vector . should_equal [Nothing, Nothing, 1, 2, 3, 100, 4]
-                    t3.at "A" . to_vector . should_equal [Nothing, Nothing, "B", "C", "D", "X", "E"]
-                    t3.at "Right_X" . to_vector . should_equal [2, 3, Nothing, 0, 1, 1, 2]
-                    t3.at "Right_A" . to_vector . should_equal ["X", "E", Nothing, "B", "C", "C", "D"]
-                False -> Nothing
+            expect_column_names ["X", "Y", "A", "Right_X", "Right_Y", "Right_A"] t3
+            t3.at "X" . to_vector . should_equal [Nothing, Nothing, 0, 1, 2, 2, 3]
+            t3.at "Right_Y" . to_vector . should_equal [100, 4, Nothing, 1, 2, 2, 3]
+
+            t3.at "Y" . to_vector . should_equal [Nothing, Nothing, 1, 2, 3, 100, 4]
+            t3.at "A" . to_vector . should_equal [Nothing, Nothing, "B", "C", "D", "X", "E"]
+            t3.at "Right_X" . to_vector . should_equal [2, 3, Nothing, 0, 1, 1, 2]
+            t3.at "Right_A" . to_vector . should_equal ["X", "E", Nothing, "B", "C", "C", "D"]
 
             t4 = table_builder [["X", [Nothing, "a", "B"]], ["Y", ["ą", "b", Nothing]], ["Z", [1, 2, 3]]]
             t5 = t4.join t4 on=(Join_Condition.Equals_Ignore_Case left="Y" right="X") |> materialize |> _.order_by ["Y"]
@@ -487,21 +479,17 @@ spec setup =
                 r3.at 4 . should_equal [2, 3, 2, 5]
 
             t4 = t1.join t2 on=[Join_Condition.Equals "A" "C"] join_kind=Join_Kind.Full
-            case setup.test_selection.supports_full_join of
-                True ->
-                    expect_column_names ["A", "B", "C", "D"] t4
-                    r4 = materialize t4 . order_by ["A", "B", "D", "C"] . rows . map .to_vector
-                    within_table t4 <|
-                        r4.length . should_equal 7
-                        r4.at 0 . should_equal [Nothing, Nothing, Nothing, Nothing]
-                        r4.at 1 . should_equal [Nothing, Nothing, 4, Nothing]
-                        r4.at 2 . should_equal [Nothing, Nothing, Nothing, 6]
-                        r4.at 3 . should_equal [Nothing, 4, Nothing, Nothing]
-                        r4.at 4 . should_equal [Nothing, 4, Nothing, 6]
-                        r4.at 5 . should_equal [1, 7, Nothing, Nothing]
-                        r4.at 6 . should_equal [2, 3, 2, 5]
-                False ->
-                    (materialize t4) . should_fail_with Unsupported_Database_Operation
+            expect_column_names ["A", "B", "C", "D"] t4
+            r4 = materialize t4 . order_by ["A", "B", "D", "C"] . rows . map .to_vector
+            within_table t4 <|
+                r4.length . should_equal 7
+                r4.at 0 . should_equal [Nothing, Nothing, Nothing, Nothing]
+                r4.at 1 . should_equal [Nothing, Nothing, 4, Nothing]
+                r4.at 2 . should_equal [Nothing, Nothing, Nothing, 6]
+                r4.at 3 . should_equal [Nothing, 4, Nothing, Nothing]
+                r4.at 4 . should_equal [Nothing, 4, Nothing, 6]
+                r4.at 5 . should_equal [1, 7, Nothing, Nothing]
+                r4.at 6 . should_equal [2, 3, 2, 5]
 
             t4_2 = t1.join t2 on=[Join_Condition.Equals "A" "C"] join_kind=Join_Kind.Left_Outer
             expect_column_names ["A", "B", "C", "D"] t4_2
@@ -617,7 +605,7 @@ spec setup =
             r2.at 0 . should_equal [2, 20, 5, 5, 100]
             r2.at 1 . should_equal [3, 30, 7, 7, 200]
 
-        Test.specify "should allow full joins with more complex join conditions" pending=(if setup.test_selection.supports_full_join.not then "Full join workaround is not implemented for this backend yet.") <|
+        Test.specify "should allow full joins with more complex join conditions" <|
             t1 = table_builder [["X", ["a", "b", "c"]], ["Y", [10, 20, 30]]]
             t2 = table_builder [["X", ["Ć", "A", "b"]], ["Z", [100, 200, 300]]]
 

test/Table_Tests/src/Common_Table_Operations/Main.enso

@@ -81,17 +81,14 @@ type Test_Selection
        - is_nan_and_nothing_distinct: Specifies if the backend is able to
          distinguish between a decimal NaN value and a missing value (Enso's
          Nothing, or SQL's NULL). If `False`, NaN is treated as a NULL.
-       - supports_full_join: Specifies if the backend supports full joins.
-         SQLite doesn't so we need to disable them until we implement a proper
-         workaround.
        - distinct_returns_first_row_from_group_if_ordered: If `order_by` was
          applied before, the distinct operation will return the first row from
          each group. Guaranteed in the in-memory backend, but may not be
          supported by all databases.
        - date_time: Specifies if the backend supports date/time operations.
        - fixed_length_text_columns: Specifies if the backend supports fixed
          length text columns.
-    Config supports_case_sensitive_columns=True order_by=True natural_ordering=False case_insensitive_ordering=True order_by_unicode_normalization_by_default=False case_insensitive_ascii_only=False take_drop=True allows_mixed_type_comparisons=True supports_unicode_normalization=False is_nan_and_nothing_distinct=True supports_full_join=True distinct_returns_first_row_from_group_if_ordered=True date_time=True fixed_length_text_columns=False
+    Config supports_case_sensitive_columns=True order_by=True natural_ordering=False case_insensitive_ordering=True order_by_unicode_normalization_by_default=False case_insensitive_ascii_only=False take_drop=True allows_mixed_type_comparisons=True supports_unicode_normalization=False is_nan_and_nothing_distinct=True distinct_returns_first_row_from_group_if_ordered=True date_time=True fixed_length_text_columns=False
 
 spec setup =
     Core_Spec.spec setup

test/Table_Tests/src/Database/SQLite_Spec.enso

@@ -120,7 +120,7 @@ sqlite_spec connection prefix =
     Common_Spec.spec prefix connection
     sqlite_specific_spec prefix connection
 
-    common_selection = Common_Table_Operations.Main.Test_Selection.Config supports_case_sensitive_columns=False order_by=True natural_ordering=False case_insensitive_ordering=True case_insensitive_ascii_only=True take_drop=False is_nan_and_nothing_distinct=False supports_full_join=False date_time=False
+    common_selection = Common_Table_Operations.Main.Test_Selection.Config supports_case_sensitive_columns=False order_by=True natural_ordering=False case_insensitive_ordering=True case_insensitive_ascii_only=True take_drop=False is_nan_and_nothing_distinct=False date_time=False
 
     ## For now `advanced_stats`, `first_last`, `text_shortest_longest` and
        `multi_distinct` remain disabled, because SQLite does not provide the