Added database support for empty receipts (i.e. when a user didn't issue any transactions during a receipt period)

matemat/db/facade.py

@@ -606,7 +606,7 @@ class MatematDatabase(object):
         transactions: List[Transaction] = []
         with self.db.transaction() as cursor:
             cursor.execute('''
-            SELECT COALESCE(MAX(r.date), u.created), COALESCE(MAX(r.last_ta_id), 0)
+            SELECT COALESCE(MAX(r.date), u.created), MAX(r.last_ta_id)
             FROM users AS u
             LEFT JOIN receipts AS r
               ON r.user_id = u.user_id
@@ -647,14 +647,14 @@ class MatematDatabase(object):
                 else:
                     t = Transaction(ta_id, user, value, old_balance, datetime.fromtimestamp(date))
                 transactions.append(t)
-            if write and len(transactions) > 0:
+            if write:
                 cursor.execute('''
                 INSERT INTO receipts (user_id, first_ta_id, last_ta_id)
                   VALUES (:user_id, :first_ta, :last_ta)
                 ''', {
                     'user_id': user.id,
-                    'first_ta': transactions[0].id,
+                    'first_ta': transactions[0].id if len(transactions) != 0 else None,
-                    'last_ta': transactions[-1].id
+                    'last_ta': transactions[-1].id if len(transactions) != 0 else None
                 })
                 cursor.execute('''SELECT last_insert_rowid()''')
                 receipt_id: int = int(cursor.fetchone()[0])

matemat/db/migrations.py

@@ -201,3 +201,41 @@ def migrate_schema_2_to_3(c: sqlite3.Cursor):
         ON DELETE SET NULL ON UPDATE CASCADE
     )
     ''')
+
+
+def migrate_schema_3_to_4(c: sqlite3.Cursor):
+    # Change receipts schema to allow null for transaction IDs
+    c.execute('''
+    CREATE TEMPORARY TABLE receipts_temp (
+      receipt_id INTEGER PRIMARY KEY,
+      user_id INTEGER NOT NULL,
+      first_ta_id INTEGER DEFAULT NULL,
+      last_ta_id INTEGER DEFAULT NULL,
+      date INTEGER(8) DEFAULT (STRFTIME('%s', 'now')),
+      FOREIGN KEY (user_id) REFERENCES users(user_id)
+        ON DELETE CASCADE ON UPDATE CASCADE,
+      FOREIGN KEY (first_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE,
+      FOREIGN KEY (last_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE
+    );
+    ''')
+    c.execute('INSERT INTO receipts_temp SELECT * FROM receipts')
+    c.execute('DROP TABLE receipts')
+    c.execute('''
+    CREATE TABLE receipts (
+      receipt_id INTEGER PRIMARY KEY,
+      user_id INTEGER NOT NULL,
+      first_ta_id INTEGER DEFAULT NULL,
+      last_ta_id INTEGER DEFAULT NULL,
+      date INTEGER(8) DEFAULT (STRFTIME('%s', 'now')),
+      FOREIGN KEY (user_id) REFERENCES users(user_id)
+        ON DELETE CASCADE ON UPDATE CASCADE,
+      FOREIGN KEY (first_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE,
+      FOREIGN KEY (last_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE
+    );
+    ''')
+    c.execute('INSERT INTO receipts SELECT * FROM receipts_temp')
+    c.execute('DROP TABLE receipts_temp')

matemat/db/schemas.py

@@ -178,3 +178,80 @@ SCHEMAS[3] = [
         ON DELETE SET NULL ON UPDATE CASCADE
     );
     ''']
+
+SCHEMAS[4] = [
+    '''
+    CREATE TABLE users (
+      user_id INTEGER PRIMARY KEY,
+      username TEXT UNIQUE NOT NULL,
+      email TEXT DEFAULT NULL,
+      password TEXT NOT NULL,
+      touchkey TEXT DEFAULT NULL,
+      is_admin INTEGER(1) NOT NULL DEFAULT 0,
+      is_member INTEGER(1) NOT NULL DEFAULT 1,
+      balance INTEGER(8) NOT NULL DEFAULT 0,
+      lastchange INTEGER(8) NOT NULL DEFAULT 0,
+      receipt_pref INTEGER(1) NOT NULL DEFAULT 0,
+      created INTEGER(8) NOT NULL DEFAULT 0
+    );
+    ''',
+    '''
+    CREATE TABLE products (
+      product_id INTEGER PRIMARY KEY,
+      name TEXT UNIQUE NOT NULL,
+      stock INTEGER(8) NOT NULL DEFAULT 0,
+      price_member INTEGER(8) NOT NULL,
+      price_non_member INTEGER(8) NOT NULL
+    );
+    ''',
+    '''
+    CREATE TABLE transactions (  -- "superclass" of the following 3 tables
+      ta_id INTEGER PRIMARY KEY,
+      user_id INTEGER DEFAULT NULL,
+      value INTEGER(8) NOT NULL,
+      old_balance INTEGER(8) NOT NULL,
+      date INTEGER(8) DEFAULT (STRFTIME('%s', 'now')),
+      FOREIGN KEY (user_id) REFERENCES users(user_id)
+        ON DELETE SET NULL ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE consumptions (  -- transactions involving buying a product
+      ta_id INTEGER PRIMARY KEY,
+      product TEXT NOT NULL,
+      FOREIGN KEY (ta_id) REFERENCES transactions(ta_id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE deposits (  -- transactions involving depositing cash
+      ta_id INTEGER PRIMARY KEY,
+      FOREIGN KEY (ta_id) REFERENCES transactions(ta_id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE modifications (  -- transactions involving balance modification by an admin
+      ta_id INTEGER NOT NULL,
+      agent TEXT NOT NULL,
+      reason TEXT DEFAULT NULL,
+      PRIMARY KEY (ta_id),
+      FOREIGN KEY (ta_id) REFERENCES transactions(ta_id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE receipts (  -- receipts sent to the users
+      receipt_id INTEGER PRIMARY KEY,
+      user_id INTEGER NOT NULL,
+      first_ta_id INTEGER DEFAULT NULL,
+      last_ta_id INTEGER DEFAULT NULL,
+      date INTEGER(8) DEFAULT (STRFTIME('%s', 'now')),
+      FOREIGN KEY (user_id) REFERENCES users(user_id)
+        ON DELETE CASCADE ON UPDATE CASCADE,
+      FOREIGN KEY (first_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE,
+      FOREIGN KEY (last_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE
+    );
+    ''']

matemat/db/test/test_migrations.py

@@ -183,3 +183,36 @@ class TestMigrations(unittest.TestCase):
         self.assertEqual('Flora Power Mate', cursor.fetchone()[0])
         cursor.execute('''SELECT product FROM consumptions WHERE ta_id = 5''')
         self.assertEqual('<unknown>', cursor.fetchone()[0])
+
+    def test_upgrade_3_to_4(self):
+        # Setup test db with example entries to test schema change
+        self._initialize_db(3)
+        cursor: sqlite3.Cursor = self.db._sqlite_db.cursor()
+        cursor.execute('''
+            INSERT INTO users VALUES
+              (1, 'testadmin', 'a@b.c', '$2a$10$herebehashes', NULL, 1, 1, 1337, 0, 0, 0)
+        ''')
+        cursor.execute('''
+            INSERT INTO products VALUES
+              (1, 'Club Mate', 42, 200, 250)
+        ''')
+        cursor.execute('''
+            INSERT INTO transactions VALUES (1, 1, 4200, 0, 1000)
+        ''')
+        cursor.execute('''
+            INSERT INTO receipts VALUES (1, 1, 1, 1, 1337)
+        ''')
+        cursor.execute('PRAGMA user_version = 3')
+
+        # Kick off the migration
+        schema_version = self.db.SCHEMA_VERSION
+        self.db.SCHEMA_VERSION = 4
+        self.db._setup()
+        self.db.SCHEMA_VERSION = schema_version
+
+        # Make sure entries from the receipts table are preserved
+        cursor.execute('''SELECT COUNT(receipt_id) FROM receipts''')
+        self.assertEqual(1, cursor.fetchone()[0])
+
+        # Make sure transaction IDs can be set to NULL
+        cursor.execute('UPDATE receipts SET first_ta_id = NULL, last_ta_id = NULL')

matemat/db/wrapper.py

@@ -2,11 +2,9 @@
 from __future__ import annotations
 from typing import Any, Optional
 
-import sqlite3
-
 from matemat.exceptions import DatabaseConsistencyError
 from matemat.db.schemas import SCHEMAS
-from matemat.db.migrations import migrate_schema_1_to_2, migrate_schema_2_to_3
+from matemat.db.migrations import *
 
 
 class DatabaseTransaction(object):
@@ -43,7 +41,7 @@ class DatabaseTransaction(object):
 
 class DatabaseWrapper(object):
 
-    SCHEMA_VERSION = 3
+    SCHEMA_VERSION = 4
 
     def __init__(self, filename: str) -> None:
         self._filename: str = filename
@@ -86,6 +84,8 @@ class DatabaseWrapper(object):
                 migrate_schema_1_to_2(c)
             if from_version <= 2 and to_version >= 3:
                 migrate_schema_2_to_3(c)
+            if from_version <= 3 and to_version >= 4:
+                migrate_schema_3_to_4(c)
 
     def connect(self) -> None:
         if self.is_connected():