From 102581e7333701ef37a49af2a99221216bcd7cea Mon Sep 17 00:00:00 2001
From: Evgeny Skvortsov <71790359+EvgSkv@users.noreply.github.com>
Date: Fri, 10 Jan 2025 22:47:37 -0800
Subject: [PATCH] Making DuckDB to be the default engine.

---
 common/logica_lib.py                           |  5 +++++
 common/sqlite3_logica.py                       |  5 +++++
 compiler/universe.py                           |  2 +-
 integration_tests/analytic_test.l              |  2 ++
 integration_tests/arg_min_max_test.l           |  2 ++
 integration_tests/array_test.l                 |  2 ++
 integration_tests/bulk_functions.l             |  2 ++
 integration_tests/cast_test.l                  |  2 ++
 integration_tests/chain.l                      |  2 ++
 integration_tests/chain_test.l                 |  2 ++
 integration_tests/closure_test.l               |  2 ++
 integration_tests/composite_functor_test.l     |  2 ++
 integration_tests/define_aggregation.l         |  2 ++
 integration_tests/disjunction_test.l           |  2 ++
 integration_tests/duckdb_is_default.l          | 18 ++++++++++++++++++
 integration_tests/duckdb_is_default.txt        |  5 +++++
 integration_tests/equals_true_test.l           |  2 ++
 integration_tests/factorial_test.l             |  1 +
 integration_tests/flags_test.l                 |  2 ++
 integration_tests/functor_annotations_test.l   |  2 ++
 integration_tests/functor_chain_test.l         |  2 ++
 integration_tests/ground_test.l                |  2 ++
 integration_tests/if_then.l                    |  2 ++
 integration_tests/import_tests/canada_test.l   |  2 ++
 integration_tests/import_tests/functor_test.l  |  2 ++
 .../import_tests/modification_inside.l         |  2 ++
 integration_tests/in_expr_test.l               |  2 ++
 integration_tests/long_functor_test.l          |  2 ++
 integration_tests/modification_inside.l        |  2 ++
 integration_tests/multi_body_aggregation.l     |  2 ++
 integration_tests/nested_combines_test.l       |  2 ++
 integration_tests/no_from_test.l               |  2 ++
 integration_tests/noinject_test.l              |  2 ++
 integration_tests/nontrivial_restof_test.l     |  2 ++
 integration_tests/operation_order_test.l       |  2 ++
 integration_tests/outer_join.l                 |  2 ++
 integration_tests/outer_join_combine.l         |  2 ++
 integration_tests/outer_join_disjunction.l     |  2 ++
 integration_tests/outer_join_some_value.l      |  2 ++
 integration_tests/outer_join_verbose.l         |  2 ++
 integration_tests/ppq_test.l                   |  2 ++
 integration_tests/quote_escape_test.l          |  2 ++
 integration_tests/reachability_test.l          |  2 ++
 integration_tests/run_tests.py                 |  2 ++
 integration_tests/simple_functors_test.l       |  2 ++
 integration_tests/single_arg_min.l             |  2 ++
 integration_tests/sql_expr_test.l              |  2 ++
 integration_tests/sql_string_table_test.l      |  2 ++
 integration_tests/sqlite_nil_test.l            |  4 ++++
 integration_tests/sub_if_test.l                |  2 ++
 integration_tests/testrun_csv_test.l           |  2 ++
 integration_tests/udf_test.l                   |  2 ++
 integration_tests/unary_test.l                 |  2 ++
 integration_tests/unnest_order_test.l          |  2 ++
 integration_tests/with_test.l                  |  2 ++
 55 files changed, 135 insertions(+), 1 deletion(-)
 create mode 100644 integration_tests/duckdb_is_default.l
 create mode 100644 integration_tests/duckdb_is_default.txt

diff --git a/common/logica_lib.py b/common/logica_lib.py
index ef50b009..c9b2c126 100644
--- a/common/logica_lib.py
+++ b/common/logica_lib.py
@@ -112,6 +112,11 @@ def RunQuery(sql,
                           '--file=/dev/stdin'] +
                           ['--output-format=ALIGNED'],
                           stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+  elif engine == 'duckdb':
+    import duckdb
+    connection = duckdb.connect()
+    df = connection.sql(sql).df()
+    return sqlite3_logica.DataframeAsArtisticTable(df)
   else:
     assert False, 'Unknown engine: %s' % engine
   o, _ = p.communicate(sql.encode())
diff --git a/common/sqlite3_logica.py b/common/sqlite3_logica.py
index d8809742..8eee6136 100644
--- a/common/sqlite3_logica.py
+++ b/common/sqlite3_logica.py
@@ -162,6 +162,11 @@ def WriteFile(filename, content):
   return 'OK'
 
 
+def DataframeAsArtisticTable(df):
+  return ArtisticTable(df.columns,
+                       list(df.itertuples(index=False, name=None)))
+
+
 def ArtisticTable(header, rows):
   """ASCII art table for query output."""
   width = [0] * len(header)
diff --git a/compiler/universe.py b/compiler/universe.py
index 17d209d2..988f643f 100755
--- a/compiler/universe.py
+++ b/compiler/universe.py
@@ -161,7 +161,7 @@ def __init__(self, rules, user_flags):
     if 'logica_default_engine' in user_flags:
       self.default_engine = user_flags['logica_default_engine']
     else:
-      self.default_engine = 'bigquery'
+      self.default_engine = 'duckdb'
 
     self.annotations = self.ExtractAnnotations(
         rules, restrict_to=['@DefineFlag', '@ResetFlagValue'])
diff --git a/integration_tests/analytic_test.l b/integration_tests/analytic_test.l
index 098ff16e..7162425d 100755
--- a/integration_tests/analytic_test.l
+++ b/integration_tests/analytic_test.l
@@ -15,6 +15,8 @@
 
 # Testing analytic functions.
 
+@Engine("bigquery");
+
 Ten() = x :- x in Range(10);
 
 Data("one_five", x, y) :-
diff --git a/integration_tests/arg_min_max_test.l b/integration_tests/arg_min_max_test.l
index c3013d91..cdaad168 100755
--- a/integration_tests/arg_min_max_test.l
+++ b/integration_tests/arg_min_max_test.l
@@ -15,6 +15,8 @@
 
 # Testing ArgMax, ArgMin, ArgMaxK and ArgMinK builtins.
 
+@Engine("bigquery");
+
 Data(v: 10, payload: "a");
 Data(v: 5, payload: "b");
 Data(v: 20, payload: "c");
diff --git a/integration_tests/array_test.l b/integration_tests/array_test.l
index 7666166b..d0156ebf 100755
--- a/integration_tests/array_test.l
+++ b/integration_tests/array_test.l
@@ -15,6 +15,8 @@
 
 # Testing array creation.
 
+@Engine("bigquery");
+
 FibonacciArray() = f :-
   f Array= (n -> ToInt64(Round((1 + 5 ^ 0.5) ^ n / (2 ^ n * 5 ^ 0.5))) :-
             n in Range(10));
diff --git a/integration_tests/bulk_functions.l b/integration_tests/bulk_functions.l
index a97ead10..8d7f8c23 100755
--- a/integration_tests/bulk_functions.l
+++ b/integration_tests/bulk_functions.l
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+@Engine("bigquery");
+
 @OrderBy(Test, "col0");
 Test("Tan") = Round(Tan(3.14159265 / 4.0), 3);
 Test("Least") = Round(Least(Sin(0.5), Sin(0.7), Sin(0.001)), 5);
diff --git a/integration_tests/cast_test.l b/integration_tests/cast_test.l
index b596f082..bfbe236f 100755
--- a/integration_tests/cast_test.l
+++ b/integration_tests/cast_test.l
@@ -15,5 +15,7 @@
 
 # Testing Cast function.
 
+@Engine("bigquery");
+
 T(true);
 T(Cast(1, "BOOL"));
diff --git a/integration_tests/chain.l b/integration_tests/chain.l
index cc4f3c35..4a5759c5 100755
--- a/integration_tests/chain.l
+++ b/integration_tests/chain.l
@@ -16,6 +16,8 @@
 # An example of a chain broken due to lack of files.
 # See chain_test on how to test it.
 
+@Engine("bigquery");
+
 A("data");
 
 B(x) :- A(x);
diff --git a/integration_tests/chain_test.l b/integration_tests/chain_test.l
index 897de151..00e60070 100755
--- a/integration_tests/chain_test.l
+++ b/integration_tests/chain_test.l
@@ -19,6 +19,8 @@ import integration_tests.chain.C;  # To connect.
 import integration_tests.chain.D;  # To connect.
 import integration_tests.chain.F;  # To test.
 
+@Engine("bigquery");
+
 # Mocking data.
 MockA("mock_data");
 
diff --git a/integration_tests/closure_test.l b/integration_tests/closure_test.l
index a1a5ada0..82e2378e 100644
--- a/integration_tests/closure_test.l
+++ b/integration_tests/closure_test.l
@@ -1,5 +1,7 @@
 import lib.closure.TransitiveClosure;
 
+@Engine("bigquery");
+
 Friend("Alice", "Bob");
 Friend("Bob", "Carrol");
 Friend("Bob", "Diana");
diff --git a/integration_tests/composite_functor_test.l b/integration_tests/composite_functor_test.l
index 26f7f28d..f2b47aa0 100755
--- a/integration_tests/composite_functor_test.l
+++ b/integration_tests/composite_functor_test.l
@@ -15,6 +15,8 @@
 
 # Test for composite functor.
 
+@Engine("bigquery");
+
 Traffic(campaign: 1, cookie: 100, country: "US");
 Traffic(campaign: 2, cookie: 200, country: "US");
 Traffic(campaign: 3, cookie: 300, country: "US");
diff --git a/integration_tests/define_aggregation.l b/integration_tests/define_aggregation.l
index 236f441b..2ad2ac29 100755
--- a/integration_tests/define_aggregation.l
+++ b/integration_tests/define_aggregation.l
@@ -15,6 +15,8 @@
 
 # Testing custom aggregation functions.
 
+@Engine("bigquery");
+
 SampledVisit(campaign:"1", person:123);
 SampledVisit(campaign:"1", person:125);
 SampledVisit(campaign:"2", person:155);
diff --git a/integration_tests/disjunction_test.l b/integration_tests/disjunction_test.l
index 128ba068..1d80a591 100755
--- a/integration_tests/disjunction_test.l
+++ b/integration_tests/disjunction_test.l
@@ -23,6 +23,8 @@
 # What day of the week was it?
 # Source: http://brainden.com/logic-problems.htm
 
+@Engine("bigquery");
+
 # Note that we can not factor out the logic of (x == "T" | ....) into a helper
 # function because disjunction is supported only for all-out predicates.
 @OrderBy(Options, "col0");
diff --git a/integration_tests/duckdb_is_default.l b/integration_tests/duckdb_is_default.l
new file mode 100644
index 00000000..229a0184
--- /dev/null
+++ b/integration_tests/duckdb_is_default.l
@@ -0,0 +1,18 @@
+#
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Only duckdb has UniqueNumber function.
+Test(fourty_two? Count= UniqueNumber()) distinct :-
+  i in Range(42);
\ No newline at end of file
diff --git a/integration_tests/duckdb_is_default.txt b/integration_tests/duckdb_is_default.txt
new file mode 100644
index 00000000..bb5db386
--- /dev/null
+++ b/integration_tests/duckdb_is_default.txt
@@ -0,0 +1,5 @@
++------------+
+| fourty_two |
++------------+
+| 42         |
++------------+
\ No newline at end of file
diff --git a/integration_tests/equals_true_test.l b/integration_tests/equals_true_test.l
index 85c68133..d37c0615 100644
--- a/integration_tests/equals_true_test.l
+++ b/integration_tests/equals_true_test.l
@@ -1,5 +1,7 @@
 # Testing equality of equality to true.
 
+@Engine("bigquery");
+
 Is5(x) = (x == 5);
 
 Test(x) :- Is5(x) == true, x in Range(10);
\ No newline at end of file
diff --git a/integration_tests/factorial_test.l b/integration_tests/factorial_test.l
index ffda4d9f..dfa90de4 100755
--- a/integration_tests/factorial_test.l
+++ b/integration_tests/factorial_test.l
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+@Engine("bigquery");
 
 Prod(x) = Exp(Sum(Log(x)));
 
diff --git a/integration_tests/flags_test.l b/integration_tests/flags_test.l
index 9f2c7998..c1c330c9 100755
--- a/integration_tests/flags_test.l
+++ b/integration_tests/flags_test.l
@@ -16,6 +16,8 @@
 # Example of running:
 # yodaql --f=a=my_value flags_test_manual.ydg testrun FlagValues
 
+@Engine("bigquery");
+
 @DefineFlag("a", "default_value_for_a");
 @DefineFlag("b", "default_value_for_b");
 @DefineFlag("c", "default_value_for_c");
diff --git a/integration_tests/functor_annotations_test.l b/integration_tests/functor_annotations_test.l
index 72abe121..7b706de6 100755
--- a/integration_tests/functor_annotations_test.l
+++ b/integration_tests/functor_annotations_test.l
@@ -17,6 +17,8 @@
 # Predicates are meaningless. Simply creating a deep call stack and calling the
 # functor.
 
+@Engine("bigquery");
+
 @Ground(L0);
 L0() = 0;
 L1() = L0() + 1;
diff --git a/integration_tests/functor_chain_test.l b/integration_tests/functor_chain_test.l
index ee0309ad..7c08c8a2 100644
--- a/integration_tests/functor_chain_test.l
+++ b/integration_tests/functor_chain_test.l
@@ -15,6 +15,8 @@
 
 # Verifying functor call for a chain.
 
+@Engine("bigquery");
+
 A(0);
 B(x) :- A(x);
 C(x) :- B(x);
diff --git a/integration_tests/ground_test.l b/integration_tests/ground_test.l
index 5385f300..10b76134 100755
--- a/integration_tests/ground_test.l
+++ b/integration_tests/ground_test.l
@@ -15,6 +15,8 @@
 
 # Testing default ground and grounding a predicate to another.
 
+@Engine("bigquery");
+
 @Ground(A);
 A("a");
 
diff --git a/integration_tests/if_then.l b/integration_tests/if_then.l
index 79c20c93..81d4a77d 100755
--- a/integration_tests/if_then.l
+++ b/integration_tests/if_then.l
@@ -15,6 +15,8 @@
 
 # Testing implication and OrderBy annotation.
 
+@Engine("bigquery");
+
 N(n1 + n2 * 5 + n3 * 25) :- l == [0,1,2,3,4], n1 in l, n2 in l, n3 in l;
 
 Qualify(n) = (
diff --git a/integration_tests/import_tests/canada_test.l b/integration_tests/import_tests/canada_test.l
index fb24b692..0d8f9831 100755
--- a/integration_tests/import_tests/canada_test.l
+++ b/integration_tests/import_tests/canada_test.l
@@ -19,6 +19,8 @@ import integration_tests.import_tests.canada.Consume;
 import integration_tests.import_tests.canada.ImportCost;
 import integration_tests.import_tests.canada.DomesticCost;
 
+@Engine("bigquery");
+
 TestImportFraction() =
     Format("%.3f", import_cost / (import_cost + domestic_cost)) :-
   import_cost == ImportCost(), domestic_cost == DomesticCost();
diff --git a/integration_tests/import_tests/functor_test.l b/integration_tests/import_tests/functor_test.l
index 342c6a89..9aeb3787 100755
--- a/integration_tests/import_tests/functor_test.l
+++ b/integration_tests/import_tests/functor_test.l
@@ -15,5 +15,7 @@
 
 import integration_tests.import_tests.new_canada.NewCanadaConsume;
 
+@Engine("bigquery");
+
 @OrderBy(Test, "col0");
 Test(..r) :- NewCanadaConsume(..r);
diff --git a/integration_tests/import_tests/modification_inside.l b/integration_tests/import_tests/modification_inside.l
index ed2e2ff4..4d60bdb5 100755
--- a/integration_tests/import_tests/modification_inside.l
+++ b/integration_tests/import_tests/modification_inside.l
@@ -18,6 +18,8 @@
 # Main predicate: BetterCountry, which is equal to Country, except for anyone
 # who wanter have got a new washer and doesn't want a new washer any more.
 
+@Engine("bigquery");
+
 BetterCountry(better_country) :-
   Country(country),
   better_country == MakeCountryBetter(country);
diff --git a/integration_tests/in_expr_test.l b/integration_tests/in_expr_test.l
index 318be77c..ac171230 100644
--- a/integration_tests/in_expr_test.l
+++ b/integration_tests/in_expr_test.l
@@ -1,3 +1,5 @@
 # Testing 'in' as a classic function.
 
+@Engine("bigquery");
+
 Test(x, x in [1,2,3]) :- x in Range(10);
\ No newline at end of file
diff --git a/integration_tests/long_functor_test.l b/integration_tests/long_functor_test.l
index e2b38300..c4fae544 100755
--- a/integration_tests/long_functor_test.l
+++ b/integration_tests/long_functor_test.l
@@ -15,6 +15,8 @@
 
 # Testing a long sequence of Make statements.
 
+@Engine("bigquery");
+
 S("success");
 
 R(x) :- T(x);
diff --git a/integration_tests/modification_inside.l b/integration_tests/modification_inside.l
index c590b163..50d1ae85 100755
--- a/integration_tests/modification_inside.l
+++ b/integration_tests/modification_inside.l
@@ -18,6 +18,8 @@
 # Main predicate: BetterCountry, which is equal to Country, except for anyone
 # who wanted have got a new washer and doesn't want a new washer any more.
 
+@Engine("bigquery");
+
 @OrderBy(BetterCountry, "col0.name");
 BetterCountry(better_country) :-
   Country(country),
diff --git a/integration_tests/multi_body_aggregation.l b/integration_tests/multi_body_aggregation.l
index 840575c1..c04cf17b 100755
--- a/integration_tests/multi_body_aggregation.l
+++ b/integration_tests/multi_body_aggregation.l
@@ -15,6 +15,8 @@
 
 # Tests for multi-body-aggregation.
 
+@Engine("bigquery");
+
 A() += 1;
 A() += 2;
 
diff --git a/integration_tests/nested_combines_test.l b/integration_tests/nested_combines_test.l
index 1390abbd..ccafc8fc 100755
--- a/integration_tests/nested_combines_test.l
+++ b/integration_tests/nested_combines_test.l
@@ -15,6 +15,8 @@
 
 # Tests that unified combines don't confuse variables.
 
+@Engine("bigquery");
+
 A(x, y) :- x == (combine List= t * 2 :- t in y), B(y);
 B(z) :- z == (combine List= t + 1 :- t in [1,2,3]);
 
diff --git a/integration_tests/no_from_test.l b/integration_tests/no_from_test.l
index e2dd3208..94f3b8b5 100755
--- a/integration_tests/no_from_test.l
+++ b/integration_tests/no_from_test.l
@@ -16,6 +16,8 @@
 # Testing that predicates with no 'FROM' clause, but with constraints are
 # compiled correctly.
 
+@Engine("bigquery");
+
 A() += 1;
 
 Test(x) :- x == "a", x == "b";
diff --git a/integration_tests/noinject_test.l b/integration_tests/noinject_test.l
index 3f9f1da1..7f9a0b92 100755
--- a/integration_tests/noinject_test.l
+++ b/integration_tests/noinject_test.l
@@ -15,6 +15,8 @@
 
 # @NoInject annotation test.
 
+@Engine("bigquery");
+
 @NoInject(A);
 A(x + x * x) :- x in [1,2,3];
 
diff --git a/integration_tests/nontrivial_restof_test.l b/integration_tests/nontrivial_restof_test.l
index 2763fafb..f2e78db9 100755
--- a/integration_tests/nontrivial_restof_test.l
+++ b/integration_tests/nontrivial_restof_test.l
@@ -15,6 +15,8 @@
 
 # Testing non-trivial rest-of field.
 
+@Engine("bigquery");
+
 T(a: 1, b: 2, c: 3, d: "a");
 T(a: 4, b: 5, c: 6, d: "b");
 T(a: 7, b: 8, c: 9, d: "c");
diff --git a/integration_tests/operation_order_test.l b/integration_tests/operation_order_test.l
index f03ad4df..225b43c4 100755
--- a/integration_tests/operation_order_test.l
+++ b/integration_tests/operation_order_test.l
@@ -13,4 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+@Engine("bigquery");
+
 Test() = 4 / 4 / 4;
diff --git a/integration_tests/outer_join.l b/integration_tests/outer_join.l
index e14a758c..e7a8d5eb 100755
--- a/integration_tests/outer_join.l
+++ b/integration_tests/outer_join.l
@@ -15,6 +15,8 @@
 
 # Outer join via mult-body-aggregation rules.
 
+@Engine("bigquery");
+
 Phones(person: "Peter", phone: "4251112222");
 Phones(person: "John", phone: "4251113333");
 Emails(person: "John", email: "john@salem.org");
diff --git a/integration_tests/outer_join_combine.l b/integration_tests/outer_join_combine.l
index 9c724978..60ebefb1 100755
--- a/integration_tests/outer_join_combine.l
+++ b/integration_tests/outer_join_combine.l
@@ -15,6 +15,8 @@
 
 # Outer join via combine.
 
+@Engine("bigquery");
+
 Phones(person: "Peter", phone: "4251112222");
 Phones(person: "John", phone: "4251113333");
 Emails(person: "John", email: "john@salem.org");
diff --git a/integration_tests/outer_join_disjunction.l b/integration_tests/outer_join_disjunction.l
index 08b2fc5e..a2660185 100755
--- a/integration_tests/outer_join_disjunction.l
+++ b/integration_tests/outer_join_disjunction.l
@@ -15,6 +15,8 @@
 
 # Outer join via disjunction.
 
+@Engine("bigquery");
+
 Phones(person: "Peter", phone: "4251112222");
 Phones(person: "John", phone: "4251113333");
 Emails(person: "John", email: "john@salem.org");
diff --git a/integration_tests/outer_join_some_value.l b/integration_tests/outer_join_some_value.l
index 88bda523..8a474c12 100755
--- a/integration_tests/outer_join_some_value.l
+++ b/integration_tests/outer_join_some_value.l
@@ -15,6 +15,8 @@
 
 # Outer join via mult-body-aggregation rules.
 
+@Engine("bigquery");
+
 Phones(person: "Peter", phone: "4251112222");
 Phones(person: "John", phone: "4251113333");
 Emails(person: "John", email: "john@salem.org");
diff --git a/integration_tests/outer_join_verbose.l b/integration_tests/outer_join_verbose.l
index 037f87ff..a359e91f 100755
--- a/integration_tests/outer_join_verbose.l
+++ b/integration_tests/outer_join_verbose.l
@@ -15,6 +15,8 @@
 
 # Outer join without mult-body-aggregation.
 
+@Engine("bigquery");
+
 Phones(person: "Peter", phone: "4251112222");
 Phones(person: "John", phone: "4251113333");
 Emails(person: "John", email: "john@salem.org");
diff --git a/integration_tests/ppq_test.l b/integration_tests/ppq_test.l
index f61a7c4a..b145e6b5 100755
--- a/integration_tests/ppq_test.l
+++ b/integration_tests/ppq_test.l
@@ -15,6 +15,8 @@
 
 # Test for ++? operator.
 
+@Engine("bigquery");
+
 Character(full_name: "Toby the dog");
 Character(full_name: "Pete the cat");
 Character(full_name: "Sharik the dog");
diff --git a/integration_tests/quote_escape_test.l b/integration_tests/quote_escape_test.l
index be76c3fd..1d281682 100755
--- a/integration_tests/quote_escape_test.l
+++ b/integration_tests/quote_escape_test.l
@@ -15,6 +15,8 @@
 
 # This is to test escaping of quotes in command line flags.
 
+@Engine("bigquery");
+
 @DefineFlag("name", "");
 
 Q(FlagValue("name"));
diff --git a/integration_tests/reachability_test.l b/integration_tests/reachability_test.l
index 37b64479..574199c9 100644
--- a/integration_tests/reachability_test.l
+++ b/integration_tests/reachability_test.l
@@ -6,6 +6,8 @@ import lib.reachability.GraphPath;
 import lib.reachability.GP3;
 import lib.reachability.GraphDistance;
 
+@Engine("bigquery");
+
 D(a, a + 1) :- a in Range(100);
 
 @OrderBy(P, "col0", "col1");
diff --git a/integration_tests/run_tests.py b/integration_tests/run_tests.py
index 9c64ad87..98308423 100755
--- a/integration_tests/run_tests.py
+++ b/integration_tests/run_tests.py
@@ -65,6 +65,8 @@ def RunAll(test_presto=False, test_trino=False):
     RunTest("dialects/trino/joins_test")
     RunTest("dialects/trino/joins_test")
 
+  RunTest("duckdb_is_default")
+
   RunTest("bq_plusplus_test")
   RunTest("sqlite_functors_test")
 
diff --git a/integration_tests/simple_functors_test.l b/integration_tests/simple_functors_test.l
index 0fd6af1b..7368f516 100755
--- a/integration_tests/simple_functors_test.l
+++ b/integration_tests/simple_functors_test.l
@@ -15,6 +15,8 @@
 
 # Simple functor test.
 
+@Engine("bigquery");
+
 Events1(campaign: 1) :- x in [0, 0, 0];        # 3 events.
 Events1(campaign: 2) :- x in [0, 0];           # 2 events.
 Events1(campaign: 3) :- x in [0, 0, 0, 0, 0];  # etc.
diff --git a/integration_tests/single_arg_min.l b/integration_tests/single_arg_min.l
index 5fbb66aa..d87793d9 100644
--- a/integration_tests/single_arg_min.l
+++ b/integration_tests/single_arg_min.l
@@ -15,6 +15,8 @@
 
 # Testing that Arg<X> functions work for single rule.
 
+@Engine("bigquery");
+
 T1() ArgMin= 4->4;
 T2() ArgMax= 4->4;
 T3() Aggr= ArgMinK(4->4, 5);
diff --git a/integration_tests/sql_expr_test.l b/integration_tests/sql_expr_test.l
index bed4bbc8..0cb9218e 100755
--- a/integration_tests/sql_expr_test.l
+++ b/integration_tests/sql_expr_test.l
@@ -15,6 +15,8 @@
 
 # Testing SqlExpr built-in function.
 
+@Engine("bigquery");
+
 ExtractHour(datetime) =
   SqlExpr("EXTRACT(HOUR FROM {datetime})", {datetime:});
 
diff --git a/integration_tests/sql_string_table_test.l b/integration_tests/sql_string_table_test.l
index 22faf8d9..c9b4b9b8 100755
--- a/integration_tests/sql_string_table_test.l
+++ b/integration_tests/sql_string_table_test.l
@@ -17,4 +17,6 @@
 # Please never use it this way.
 # This feature is provided for Spanner indexes specification.
 
+@Engine("bigquery");
+
 Test(result) :- `((select "success" as result))`(result:);
diff --git a/integration_tests/sqlite_nil_test.l b/integration_tests/sqlite_nil_test.l
index ea1e6ada..78e837a1 100644
--- a/integration_tests/sqlite_nil_test.l
+++ b/integration_tests/sqlite_nil_test.l
@@ -16,6 +16,10 @@
 # Testing that recursion works even if some predicates have
 # no initial condition.
 
+# TODO: Seems like this test is incorrectly named to be sqlite, while
+# it's on bigquery.
+
+@Engine("bigquery");
 A() Max= 0;
 B() Max= A() + 1;
 A() Max= B() + 1;
diff --git a/integration_tests/sub_if_test.l b/integration_tests/sub_if_test.l
index 28538c3d..739607dd 100644
--- a/integration_tests/sub_if_test.l
+++ b/integration_tests/sub_if_test.l
@@ -1,5 +1,7 @@
 # Testing subscript of implication optimization.
 
+@Engine("bigquery");
+
 Test(n, a, b, c) :-
   n in Range(10),
   r == (
diff --git a/integration_tests/testrun_csv_test.l b/integration_tests/testrun_csv_test.l
index 1eaf27d4..1ba9bf6c 100755
--- a/integration_tests/testrun_csv_test.l
+++ b/integration_tests/testrun_csv_test.l
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+@Engine("bigquery");
+
 # Testing querying of CSVs in testrun mode.
 @OrderBy(Population, "state");
 Population(
diff --git a/integration_tests/udf_test.l b/integration_tests/udf_test.l
index 3d85c608..9f106600 100755
--- a/integration_tests/udf_test.l
+++ b/integration_tests/udf_test.l
@@ -15,6 +15,8 @@
 
 # Testing simple function compilation.
 
+@Engine("bigquery");
+
 # Functors of argument F.
 GridF(t) = F(t) :- t == s / 100.0 - 5, s in Range(1000);
 FunctionMinimum() = x :-
diff --git a/integration_tests/unary_test.l b/integration_tests/unary_test.l
index 2075c7d9..717e2406 100755
--- a/integration_tests/unary_test.l
+++ b/integration_tests/unary_test.l
@@ -15,6 +15,8 @@
 
 # Testing unary operators ! and -.
 
+@Engine("bigquery");
+
 Test("not") = ToString(is_small) :-
   is_small == !is_big,
   is_big == (x > 5),
diff --git a/integration_tests/unnest_order_test.l b/integration_tests/unnest_order_test.l
index 07e8c6f7..06e399cc 100755
--- a/integration_tests/unnest_order_test.l
+++ b/integration_tests/unnest_order_test.l
@@ -15,6 +15,8 @@
 
 # Testing that unnestings are ordered by dependency.
 
+@Engine("bigquery");
+
 @OrderBy(Test, "col0");
 Test(x) :- x in y.a, y in [{a:[1,2,3]}];
 Test(x) :- y in [{a:[1,2,3]}], x in y.a;
diff --git a/integration_tests/with_test.l b/integration_tests/with_test.l
index 4aa0ce65..a8e16f50 100755
--- a/integration_tests/with_test.l
+++ b/integration_tests/with_test.l
@@ -15,6 +15,8 @@
 
 # Testing 'With' annotation.
 
+@Engine("bigquery");
+
 @With(Parent);
 Parent("A", "B");
 Parent("B", "C");