Add mass objects

datalite/__init__.py

@@ -1,2 +1,2 @@
-__all__ = ['commons', 'datalite_decorator', 'fetch', 'migrations', 'datalite', 'constraints']
+__all__ = ['commons', 'datalite_decorator', 'fetch', 'migrations', 'datalite', 'constraints', 'mass_actions']
 from .datalite_decorator import datalite

datalite/mass_actions.py

@@ -0,0 +1,62 @@
+"""
+This module includes functions to insert multiple records
+    to a bound database at one time, with one time open and closing
+    of the database file.
+"""
+from typing import TypeVar, Union, List, Tuple
+from dataclasses import asdict
+from .constraints import ConstraintFailedError
+from .commons import _convert_sql_format
+import sqlite3 as sql
+
+T = TypeVar('T')
+
+
+class MisformedCollectionError(Exception):
+    pass
+
+
+def is_homogeneous(objects: Union[List[T], Tuple[T]]) -> bool:
+    """
+    Check if all of the members a Tuple or a List
+        is of the same type.
+
+    :param objects: Tuple or list to check.
+    :return: If all of the members of the same type.
+    """
+    class_ = objects[0].__class__
+    return all([isinstance(obj, class_) for obj in objects])
+
+
+def create_many_entries(objects: Union[List[T], Tuple[T]]) -> None:
+    """
+    Insert many records corresponding to objects
+        in a tuple or a list.
+
+    :param objects: A tuple or a list of objects decorated
+        with datalite.
+    :return: None.
+    """
+    if not objects or not is_homogeneous(objects):
+        raise MisformedCollectionError("Tuple or List is empty or homogeneous.")
+    sql_queries = []
+    first_index: int = 0
+    table_name = objects[0].__class__.__name__.lower()
+    for obj in objects:
+        kv_pairs = asdict(obj).items()
+        sql_queries.append(f"INSERT INTO {table_name}(" +
+                           f"{', '.join(item[0] for item in kv_pairs)})" +
+                           f" VALUES ({', '.join(_convert_sql_format(item[1]) for item in kv_pairs)});")
+    with sql.connect(getattr(objects[0], "db_path")) as con:
+        cur: sql.Cursor = con.cursor()
+        try:
+            cur.execute(f"SELECT obj_id FROM {table_name} ORDER BY obj_id DESC LIMIT 1")
+            index_tuple = cur.fetchone()
+            if index_tuple:
+                first_index = index_tuple[0]
+            cur.executescript('\n'.join(sql_queries))
+        except sql.IntegrityError:
+            raise ConstraintFailedError
+        con.commit()
+    for i, obj in enumerate(objects):
+        setattr(obj, "obj_id", first_index + i)

docs/datalite.rst

@@ -22,6 +22,14 @@ datalite.fetch module
    :undoc-members:
    :show-inheritance:
 
+datalite.mass_actions module
+------------------------------
+
+.. automodule:: datalite.mass_actions
+    :members:
+    :undoc-members:
+    :show-inheritence:
+
 datalite.migrations module
 ----------------------------
 

test/main_tests.py

@@ -2,11 +2,10 @@ import unittest
 from datalite import datalite
 from datalite.constraints import Unique, ConstraintFailedError
 from datalite.fetch import fetch_if, fetch_all, fetch_range, fetch_from, fetch_equals, fetch_where
+from datalite.mass_actions import create_many_entries
 from sqlite3 import connect
 from dataclasses import dataclass, asdict
 from math import floor
-from os import remove
-
 from datalite.migrations import basic_migrate, _drop_table
 
 
@@ -51,6 +50,12 @@ class ConstraintedClass:
     unique_str: Unique[str]
 
 
+@datalite(db_path='test.db')
+@dataclass
+class MassCommit:
+    str_: str
+
+
 def getValFromDB(obj_id = 1):
     with connect('test.db') as db:
         cur = db.cursor()
@@ -190,5 +195,16 @@ class DatabaseConstraints(unittest.TestCase):
         self.obj.remove_entry()
 
 
+class DatabaseMassInsert(unittest.TestCase):
+    def setUp(self) -> None:
+        self.objs = [MassCommit('cat') for _ in range(30)]
+
+    def testMassCreate(self):
+        create_many_entries(self.objs)
+
+    def tearDown(self) -> None:
+        [obj.remove_entry() for obj in self.objs]
+
+
 if __name__ == '__main__':
     unittest.main()