Implement tables.patch RPC endpoint

db/sql/00_msar.sql

@@ -1057,7 +1057,7 @@ Args:
   new_tab_name: unquoted, unqualified table name
 */
 BEGIN
-  RETURN __msar.rename_table(__msar.get_relation_name(tab_id), quote_ident(new_tab_name));
+  RETURN __msar.rename_table(msar.get_relation_name_or_null(tab_id), quote_ident(new_tab_name));
 END;
 $$ LANGUAGE plpgsql RETURNS NULL ON NULL INPUT;
 
@@ -1089,8 +1089,12 @@ Args:
   tab_name: The qualified, quoted name of the table whose comment we will change.
   comment_: The new comment. Any quotes or special characters must be escaped.
 */
-SELECT __msar.exec_ddl('COMMENT ON TABLE %s IS %s', tab_name, comment_);
-$$ LANGUAGE SQL RETURNS NULL ON NULL INPUT;
+DECLARE
+  comment_or_null text := COALESCE(comment_, 'NULL');
+BEGIN
+RETURN __msar.exec_ddl('COMMENT ON TABLE %s IS %s', tab_name, comment_or_null);
+END;
+$$ LANGUAGE plpgsql;
 
 
 CREATE OR REPLACE FUNCTION
@@ -1101,8 +1105,8 @@ Args:
   tab_id: The OID of the table whose comment we will change.
   comment_: The new comment.
 */
-SELECT __msar.comment_on_table(__msar.get_relation_name(tab_id), quote_literal(comment_));
-$$ LANGUAGE SQL RETURNS NULL ON NULL INPUT;
+SELECT __msar.comment_on_table(msar.get_relation_name_or_null(tab_id), quote_literal(comment_));
+$$ LANGUAGE SQL;
 
 
 CREATE OR REPLACE FUNCTION
@@ -1118,10 +1122,40 @@ SELECT __msar.comment_on_table(
   msar.get_fully_qualified_object_name(sch_name, tab_name),
   quote_literal(comment_)
 );
-$$ LANGUAGE SQL RETURNS NULL ON NULL INPUT;
+$$ LANGUAGE SQL;
+
+
+-- Alter table -------------------------------------------------------------------------------------
+CREATE OR REPLACE FUNCTION
+msar.alter_table(tab_id oid, tab_alters jsonb) RETURNS text AS $$/*
+Alter columns of the given table in bulk, returning the IDs of the columns so altered.
+
+Args:
+  tab_id: The OID of the table whose columns we'll alter.
+  tab_alters: a JSONB describing the alterations to make.
 
+  The tab_alters should have the form:
+  {
+    "name": <str>,
+    "description": <str>
+    "columns": <col_alters>,
+  }
+*/
+DECLARE
+  new_tab_name text;
+  comment text;
+  col_alters jsonb;
+BEGIN
+  new_tab_name := tab_alters->>'name';
+  comment := tab_alters->>'description';
+  col_alters := tab_alters->'columns';
+  PERFORM msar.rename_table(tab_id, new_tab_name);
+  PERFORM msar.comment_on_table(tab_id, comment);
+  PERFORM msar.alter_columns(tab_id, col_alters);
+  RETURN msar.get_relation_name_or_null(tab_id);
+END;
+$$ LANGUAGE plpgsql RETURNS NULL ON NULL INPUT;
 
--- Alter Table: LEFT IN PYTHON (for now) -----------------------------------------------------------
 
 ----------------------------------------------------------------------------------------------------
 ----------------------------------------------------------------------------------------------------

db/tables/operations/alter.py

@@ -50,6 +50,26 @@ def alter_table(table_name, table_oid, schema, engine, update_data):
         batch_update_columns(table_oid, engine, update_data['columns'])
 
 
+def alter_table_on_database(table_oid, table_data_dict, conn):
+    """
+    Alter the name, description, or columns of a table, returning name of the altered table.
+
+    Args:
+        table_oid: The OID of the table to be altered.
+        table_data_dict: A dict describing the alterations to make.
+
+    table_data_dict should have the form:
+    {
+        "name": <str>,
+        "description": <str>,
+        "columns": <list> of column_data describing columns to alter.
+    }
+    """
+    return db_conn.exec_msar_func(
+        conn, 'alter_table', table_oid, table_data_dict
+    ).fetchone()[0]
+
+
 def update_pk_sequence_to_latest(engine, table, connection=None):
     """
     Update the primary key sequence to the current maximum.

db/tests/tables/operations/test_alter.py

@@ -29,3 +29,17 @@ def test_comment_on_table(engine_with_schema):
     assert call_args[2] == schema_name
     assert call_args[3] == "comment_on_me"
     assert call_args[4] == "This is a comment"
+
+
+def test_alter_table():
+    with patch.object(tab_alter.db_conn, 'exec_msar_func') as mock_exec:
+        tab_alter.alter_table_on_database(
+            12345,
+            {"name": "newname", "description": "this is a comment", "columns": {}},
+            "conn"
+        )
+    call_args = mock_exec.call_args_list[0][0]
+    assert call_args[0] == "conn"
+    assert call_args[1] == "alter_table"
+    assert call_args[2] == 12345
+    assert call_args[3] == {"name": "newname", "description": "this is a comment", "columns": {}}

docs/docs/api/rpc.md

@@ -64,7 +64,9 @@ To use an RPC function:
       - get
       - add
       - delete
+      - patch
       - TableInfo
+      - SettableTableInfo
 
 ---
 

mathesar/rpc/tables.py

@@ -6,7 +6,8 @@
 from db.tables.operations.select import get_table_info, get_table
 from db.tables.operations.drop import drop_table_from_database
 from db.tables.operations.create import create_table_on_database
-from mathesar.rpc.columns import CreateableColumnInfo
+from db.tables.operations.alter import alter_table_on_database
+from mathesar.rpc.columns import CreateableColumnInfo, SettableColumnInfo
 from mathesar.rpc.constraints import CreateableConstraintInfo
 from mathesar.rpc.exceptions.handlers import handle_rpc_exceptions
 from mathesar.rpc.utils import connect
@@ -28,6 +29,27 @@ class TableInfo(TypedDict):
     description: Optional[str]
 
 
+class SettableTableInfo(TypedDict):
+    """
+    Information about a table, restricted to settable fields.
+
+    When possible, Passing `null` for a key will clear the underlying
+    setting. E.g.,
+
+    - `description = null` clears the table description.
+
+    Setting any of `name`, `columns` to `null` is a noop.
+
+    Attributes:
+        name: The new name of the table.
+        description: The description of the table.
+        columns: A list describing desired column alterations.
+    """
+    name: Optional[str]
+    description: Optional[str]
+    columns: Optional[list[SettableColumnInfo]]
+
+
 @rpc_method(name="tables.list")
 @http_basic_auth_login_required
 @handle_rpc_exceptions
@@ -125,3 +147,25 @@ def delete(
     user = kwargs.get(REQUEST_KEY).user
     with connect(database_id, user) as conn:
         return drop_table_from_database(table_oid, conn, cascade)
+
+
+@rpc_method(name="tables.patch")
+@http_basic_auth_login_required
+@handle_rpc_exceptions
+def patch(
+    *, table_oid: str, table_data_dict: SettableTableInfo, database_id: int, **kwargs
+) -> str:
+    """
+    Alter details of a preexisting table in a database.
+
+    Args:
+        table_oid: Identity of the table whose name, description or columns we'll modify.
+        table_data_dict: A list describing desired table alterations.
+        database_id: The Django id of the database containing the table.
+
+    Returns:
+        The name of the altered table.
+    """
+    user = kwargs.get(REQUEST_KEY).user
+    with connect(database_id, user) as conn:
+        return alter_table_on_database(table_oid, table_data_dict, conn)

mathesar/tests/rpc/test_endpoints.py

@@ -68,6 +68,11 @@
         tables.delete,
         "tables.delete",
         [user_is_authenticated]
+    ),
+    (
+        tables.patch,
+        "tables.patch",
+        [user_is_authenticated]
     )
 ]
 

mathesar/tests/rpc/test_tables.py

@@ -152,3 +152,43 @@ def mock_table_add(table_name, _schema_oid, conn, column_data_list, constraint_d
     monkeypatch.setattr(tables, 'create_table_on_database', mock_table_add)
     actual_table_oid = tables.add(table_name='newtable', schema_oid=2200, database_id=11, request=request)
     assert actual_table_oid == 1964474
+
+
+def test_tables_patch(rf, monkeypatch):
+    request = rf.post('/api/rpc/v0', data={})
+    request.user = User(username='alice', password='pass1234')
+    table_oid = 1964474
+    database_id = 11
+    table_data_dict = {
+        "name": "newtabname",
+        "description": "this is a description",
+        "columns": {}
+    }
+
+    @contextmanager
+    def mock_connect(_database_id, user):
+        if _database_id == database_id and user.username == 'alice':
+            try:
+                yield True
+            finally:
+                pass
+        else:
+            raise AssertionError('incorrect parameters passed')
+
+    def mock_table_patch(_table_oid, _table_data_dict, conn):
+        if _table_oid != table_oid and _table_data_dict != table_data_dict:
+            raise AssertionError('incorrect parameters passed')
+        return 'newtabname'
+    monkeypatch.setattr(tables, 'connect', mock_connect)
+    monkeypatch.setattr(tables, 'alter_table_on_database', mock_table_patch)
+    altered_table_name = tables.patch(
+        table_oid=1964474,
+        table_data_dict={
+            "name": "newtabname",
+            "description": "this is a description",
+            "columns": {}
+        },
+        database_id=11,
+        request=request
+    )
+    assert altered_table_name == 'newtabname'