Emulate foreign keys for multi tables over SQL adapter (#7994)

edb/pgsql/metaschema.py

@@ -6682,22 +6682,18 @@ def _generate_sql_information_schema(
             pa.attrelid as pc_oid,
             pa.*,
             pa.tableoid, pa.xmin, pa.cmin, pa.xmax, pa.cmax, pa.ctid
-        FROM edgedb_VER."_SchemaPointer" sp
+        FROM edgedb_VER."_SchemaProperty" sp
         JOIN pg_class pc ON pc.relname = sp.id::TEXT
         JOIN pg_attribute pa ON pa.attrelid = pc.oid
 
-        -- needed for filtering out links
-        LEFT JOIN edgedb_VER."_SchemaLink" sl ON sl.id = sp.id
-
         -- positions for special pointers
         JOIN (
             VALUES  ('source', 0),
                     ('target', 1)
         ) spec(k, position) ON (spec.k = pa.attname)
 
         WHERE
-            sl.id IS NULL -- property (non-link)
-            AND sp.cardinality = 'Many' -- multi
+            sp.cardinality = 'Many' -- multi
             AND sp.expr IS NULL -- non-computed
 
         UNION ALL
@@ -6812,7 +6808,10 @@ def _generate_sql_information_schema(
         trampoline.VersionedView(
             name=("edgedbsql", "pg_constraint"),
             query=r"""
-        -- primary keys
+        -- primary keys for:
+        --  - objects tables (that contains id)
+        --  - link tables (that contains source and target)
+        -- there exists a unique constraint for each of these
         SELECT
           pc.oid,
           vt.table_name || '_pk' AS conname,
@@ -6825,32 +6824,38 @@ def _generate_sql_information_schema(
           pc.contypid,
           pc.conindid,
           pc.conparentid,
-          pc.confrelid,
-          pc.confupdtype,
-          pc.confdeltype,
-          pc.confmatchtype,
+          NULL::oid AS confrelid,
+          NULL::"char" AS confupdtype,
+          NULL::"char" AS confdeltype,
+          NULL::"char" AS confmatchtype,
           pc.conislocal,
           pc.coninhcount,
           pc.connoinherit,
-          pc.conkey,
-          pc.confkey,
-          pc.conpfeqop,
-          pc.conppeqop,
-          pc.conffeqop,
-          pc.confdelsetcols,
-          pc.conexclop,
+          CASE WHEN pa.attname = 'id'
+            THEN ARRAY[1]::int2[] -- id will always have attnum 1
+            ELSE ARRAY[1, 2]::int2[] -- source and target
+          END AS conkey,
+          NULL::int2[] AS confkey,
+          NULL::oid[] AS conpfeqop,
+          NULL::oid[] AS conppeqop,
+          NULL::oid[] AS conffeqop,
+          NULL::int2[] AS confdelsetcols,
+          NULL::oid[] AS conexclop,
           pc.conbin,
           pc.tableoid, pc.xmin, pc.cmin, pc.xmax, pc.cmax, pc.ctid
         FROM pg_constraint pc
         JOIN edgedbsql_VER.pg_class_tables pct ON pct.oid = pc.conrelid
         JOIN edgedbsql_VER.virtual_tables vt ON vt.pg_type_id = pct.reltype
-        JOIN pg_attribute pa ON (pa.attname = 'id' AND pa.attrelid = pct.oid)
+        JOIN pg_attribute pa
+          ON (pa.attrelid = pct.oid
+              AND pa.attnum = ANY(conkey)
+              AND pa.attname IN ('id', 'source')
+             )
         WHERE contype = 'u' -- our ids and all links will have unique constraint
-          AND attnum = ANY(conkey)
 
         UNION ALL
 
-        -- foreign keys
+        -- foreign keys for object tables
         SELECT
           edgedbsql_VER.uuid_to_oid(sl.id) as oid,
           vt.table_name || '_fk_' || sl.name AS conname,
@@ -6872,9 +6877,9 @@ def _generate_sql_information_schema(
           TRUE AS connoinherit,
           ARRAY[pa.attnum]::int2[] AS conkey,
           ARRAY[1]::int2[] AS confkey, -- id will always have attnum 1
-          ARRAY[2972]::oid[] AS conpfeqop, -- 2972 is eq comparison for uuids
-          ARRAY[2972]::oid[] AS conppeqop, -- 2972 is eq comparison for uuids
-          ARRAY[2972]::oid[] AS conffeqop, -- 2972 is eq comparison for uuids
+          ARRAY['uuid_eq'::regproc]::oid[] AS conpfeqop,
+          ARRAY['uuid_eq'::regproc]::oid[] AS conppeqop,
+          ARRAY['uuid_eq'::regproc]::oid[] AS conffeqop,
           NULL::int2[] AS confdelsetcols,
           NULL::oid[] AS conexclop,
           NULL::pg_node_tree AS conbin,
@@ -6889,6 +6894,73 @@ def _generate_sql_information_schema(
         JOIN edgedbsql_VER.pg_attribute pa
           ON pa.attrelid = pc.oid
          AND pa.attname = sl.name || '_id'
+
+        UNION ALL
+
+        -- foreign keys for:
+        -- - multi link tables (source & target),
+        -- - multi property tables (source),
+        -- - single link with link properties (source & target),
+        -- these constraints do not actually exist, so we emulate it entierly
+        SELECT
+            edgedbsql_VER.uuid_to_oid(sp.id) AS oid,
+            vt.table_name || '_fk_' || spec.name AS conname,
+            edgedbsql_VER.uuid_to_oid(vt.module_id) AS connamespace,
+            'f'::"char" AS contype,
+            FALSE AS condeferrable,
+            FALSE AS condeferred,
+            TRUE AS convalidated,
+            pc.oid AS conrelid,
+            pc.reltype AS contypid,
+            0::oid AS conindid, -- TODO
+            0::oid AS conparentid,
+            pcf.oid AS confrelid,
+            'r'::"char" AS confupdtype,
+            'r'::"char" AS confdeltype,
+            's'::"char" AS confmatchtype,
+            TRUE AS conislocal,
+            0::int2 AS coninhcount,
+            TRUE AS connoinherit,
+            ARRAY[spec.attnum]::int2[] AS conkey,
+            ARRAY[1]::int2[] AS confkey,     -- id will have attnum 1
+            ARRAY['uuid_eq'::regproc]::oid[] AS conpfeqop,
+            ARRAY['uuid_eq'::regproc]::oid[] AS conppeqop,
+            ARRAY['uuid_eq'::regproc]::oid[] AS conffeqop,
+            NULL::int2[] AS confdelsetcols,
+            NULL::oid[] AS conexclop,
+            pc.relpartbound AS conbin,
+            pc.tableoid,
+            pc.xmin,
+            pc.cmin,
+            pc.xmax,
+            pc.cmax,
+            pc.ctid
+        FROM edgedb_VER."_SchemaPointer" sp
+
+        -- find links with link properties
+        LEFT JOIN LATERAL (
+            SELECT sl.id
+            FROM edgedb_VER."_SchemaLink" sl
+            LEFT JOIN edgedb_VER."_SchemaProperty" AS slp ON slp.source = sl.id
+            GROUP BY sl.id
+            HAVING COUNT(*) > 2
+        ) link_props ON link_props.id = sp.id
+
+        JOIN pg_class pc ON pc.relname = sp.id::TEXT
+        JOIN edgedbsql_VER.virtual_tables vt ON vt.pg_type_id = pc.reltype
+
+        -- duplicate each row for source and target
+        JOIN LATERAL (VALUES
+            ('source', 1::int2, sp.source),
+            ('target', 2::int2, sp.target)
+        ) spec(name, attnum, foreign_id) ON TRUE
+        JOIN edgedbsql_VER.virtual_tables vtf ON vtf.id = spec.foreign_id
+        JOIN pg_class pcf ON pcf.reltype = vtf.pg_type_id
+
+        WHERE
+            sp.cardinality = 'Many' OR link_props.id IS NOT NULL
+            AND sp.computable IS NOT TRUE
+            AND sp.internal IS NOT TRUE
         """
         ),
         trampoline.VersionedView(

edb/tools/edb.py

@@ -87,5 +87,6 @@ def load_ext(args: tuple[str, ...]):
 from . import ast_inheritance_graph  # noqa
 from . import parser_demo  # noqa
 from . import ls_forbidden_functions  # noqa
+from . import redo_metaschema  # noqa
 from .profiling import cli as prof_cli  # noqa
 from .experimental_interpreter import edb_entry # noqa

edb/tools/redo_metaschema.py

@@ -0,0 +1,52 @@
+#
+# This source file is part of the EdgeDB open source project.
+#
+# Copyright 2021-present MagicStack Inc. and the EdgeDB authors.
+#
+# 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.
+#
+
+from edb.tools.edb import edbcommands
+
+
+@edbcommands.command("redo-metaschema-sql")
+def run():
+    """
+    Generates DDL to recreate metaschema for sql introspection.
+    Can be used to apply changes to metaschema to an existing database.
+
+    edb redo-metaschema-sql | ./build/postgres/install/bin/psql \
+        "postgresql://postgres@/E_main?host=$(pwd)/tmp/devdatadir&port=5432" \
+        -v ON_ERROR_STOP=ON
+    """
+
+    from edb.common import devmode
+    devmode.enable_dev_mode()
+
+    from edb.pgsql import dbops, metaschema
+    from edb import buildmeta
+
+    version = buildmeta.get_pg_version()
+    commands = metaschema._generate_sql_information_schema(version)
+
+    for command in commands:
+        block = dbops.PLTopBlock()
+
+        if isinstance(command, dbops.CreateFunction):
+            command.or_replace = True
+        if isinstance(command, dbops.CreateView):
+            command.or_replace = True
+
+        command.generate(block)
+
+        print(block.to_string())

tests/test_sql_query.py

@@ -1040,6 +1040,50 @@ async def test_sql_query_introspection_04(self):
             ],
         )
 
+    async def test_sql_query_introspection_05(self):
+        # test pg_constraint
+
+        res = await self.squery_values(
+            '''
+            SELECT pc.relname, pcon.contype, pa.key, pcf.relname, paf.key
+            FROM pg_constraint pcon
+            JOIN pg_class pc ON pc.oid = pcon.conrelid
+            LEFT JOIN pg_class pcf ON pcf.oid = pcon.confrelid
+            LEFT JOIN LATERAL (
+                SELECT string_agg(attname, ',') as key
+                FROM pg_attribute
+                WHERE attrelid = pcon.conrelid
+                  AND attnum = ANY(pcon.conkey)
+            ) pa ON TRUE
+            LEFT JOIN LATERAL (
+                SELECT string_agg(attname, ',') as key
+                FROM pg_attribute
+                WHERE attrelid = pcon.confrelid
+                  AND attnum = ANY(pcon.confkey)
+            ) paf ON TRUE
+            WHERE pc.relname IN (
+                'Book.chapters', 'Movie', 'Movie.director', 'Movie.actors'
+            )
+            ORDER BY pc.relname ASC, pcon.contype DESC, pa.key
+            '''
+        )
+
+        self.assertEqual(
+            res,
+            [
+                ['Book.chapters', b'f', 'source', 'Book', 'id'],
+                ['Movie', b'p', 'id', None, None],
+                ['Movie', b'f', 'director_id', 'Person', 'id'],
+                ['Movie', b'f', 'genre_id', 'Genre', 'id'],
+                ['Movie.actors', b'p', 'source,target', None, None],
+                ['Movie.actors', b'f', 'source', 'Movie', 'id'],
+                ['Movie.actors', b'f', 'target', 'Person', 'id'],
+                ['Movie.director', b'p', 'source,target', None, None],
+                ['Movie.director', b'f', 'source', 'Movie', 'id'],
+                ['Movie.director', b'f', 'target', 'Person', 'id'],
+            ],
+        )
+
     async def test_sql_query_schemas_01(self):
         await self.scon.fetch('SELECT id FROM "inventory"."Item";')
         await self.scon.fetch('SELECT id FROM "public"."Person";')