diff --git a/api/s0_base.py b/api/s0_base.py
index 37917e9..37d9488 100644
--- a/api/s0_base.py
+++ b/api/s0_base.py
@@ -1,5 +1,7 @@
 from psycopg.rows import dict_row, Row
 from .connection import g_conn_dict as conn
+from .operation import *
+from .change_set import ChangeSet
 
 _NODE = "_node"
 _LINK = "_link"
@@ -73,3 +75,50 @@ def get_curves(name: str) -> list[str]:
 
 def get_patterns(name: str) -> list[str]:
     return _get_all(name, _PATTERN)
+
+def add_node(name: str, node_type: str, id: str, x: float, y: float, table_sql: str, table_undo_sql: str) -> ChangeSet:
+    if is_node(name, id):
+        return
+
+    with conn[name].cursor() as cur:
+        sql = f"insert into _node (id, type) values ('{id}', '{node_type}'); "
+        sql += table_sql
+        sql += f" insert into coordinates (node, coord) values ('{id}', '({x}, {y})');"
+        cur.execute(sql)
+
+        redo = sql.replace("'", '"')
+        undo = f'delete from coordinates where node = "{id}"; '
+        undo += table_undo_sql
+        undo += f' delete from _node where id = "{id}";'
+        add_operation(name, redo, undo)
+
+    change = ChangeSet()
+    change.add(node_type, id)
+    return change
+
+def delete_node(name: str, node_type: str, id: str, table_sql: str, table_undo_sql: str) -> ChangeSet:
+    if not is_node(name, id):
+        return
+
+    with conn[name].cursor(row_factory=dict_row) as cur:
+        cur.execute(f"select * from coordinates where node = '{id}'")
+        row = cur.fetchone()
+        if row == None:
+            return
+
+        coord = row['coord']
+
+        sql = f"delete from coordinates where node = '{id}'; "
+        sql += table_sql
+        sql += f" delete from _node where id = '{id}';"
+        cur.execute(sql)
+
+        redo = sql.replace("'", '"')
+        undo = f'insert into _node (id, type) values ("{id}", "{node_type}"); '
+        undo += table_undo_sql
+        undo += f' insert into coordinates (node, coord) values ("{id}", "{coord}");'
+        add_operation(name, redo, undo)
+
+    change = ChangeSet()
+    change.delete(node_type, id)
+    return change