2.0学习进度 任重而道远

sqlalchemy_20/db.py

@@ -1,4 +1,6 @@
-from sqlalchemy import create_engine, text, insert, update, select, delete, engine_from_config, or_, and_, func, any_
+from sqlalchemy import create_engine, text, insert, update, select, delete, intersect, engine_from_config, or_, and_, \
+    func, any_
+from sqlalchemy import MetaData, Table, Column, Integer, String, Enum, DATE
 from sqlalchemy.orm import Session, sessionmaker
 import configparser
 import sys
@@ -121,10 +123,17 @@ insert_data2 = {'name': 'sql2_test2', 'password': 'pwd2'}
 # insert 对象方式 批量
 # insert_obj2 = User(name='sql2_test8', password='pwd8')
 # with db_session as sess:
-#     # sess.bulk_save_objects([insert_obj2, insert_obj3])
+#     # sess.bulk_save_objects([insert_obj2, insert_obj3])  # 推荐
 #     sess.add_all([insert_obj2, insert_obj3])
 #     sess.commit()
 
+# insert 字典方式 批量
+# insert_dict = [{'name': 'dict1', 'password': 'dict1pwd1'}, {'name': 'dict2', 'password': 'dict2pwd2'}]
+# with db_session as sess:
+#     sess.bulk_insert_mappings(User, insert_dict)
+#     sess.commit()
+
+
 # add
 # with db_session as sess:
 #     user_obj = User(name='add', password='addpwd123')
@@ -146,6 +155,15 @@ insert_data2 = {'name': 'sql2_test2', 'password': 'pwd2'}
 # for row in query_cursor.scalars():
 #     print(row)  # row.name格式可以取到数据
 
+# limit
+# query_cursor = db_session.execute(select(User).limit(10))
+# print(query_cursor.all())  # 数据指针，当all取过数据后one将得到None
+# for row in query_cursor.scalars():
+#     print(row)  # row.name格式可以取到数据
+
+# distinct
+
+
 # sqlalchemy1.4: session.query(User).filter_by(name='roger').all()
 # sql_stmt = select(User).filter_by(name='roger')
 # query_result = db_session.execute(sql_stmt).one()
@@ -295,6 +313,54 @@ insert_data2 = {'name': 'sql2_test2', 'password': 'pwd2'}
 # func.random()
 # func.sum()
 
+
+# sqlalchemy1.4 join filter形式
+# result = session.query(User, Student).filter(User.name == Student.name).all()
+
+# sql_stmt = select(User, Student).where(User.name == Student.name)
+# query_result = db_session.execute(sql_stmt).scalars()
+# for row in query_result:
+#     print(row)
+#     print(f'{row.id}-{row.name}-{row.password}')
+
+# sqlalchemy1.4 join形式 无外键关联的情况
+# result = session.query(User).join(Student, User.name == Student.name).all()
+
+# sql_stmt = select(User).join(Student, User.name == Student.name).where(User.name.like('roger%'))
+# query_result = db_session.execute(sql_stmt).scalars()
+# for row in query_result:
+#     print(row)
+#     print(f'{row.id}-{row.name}-{row.password}')
+
+# join有外键关联的情况（Todo）
+
+# left_join outerjoin (Todo)
+
+# union
+# sqlalchemy1.4 union
+# q1 = session.query(User.name).filter(User.id > 1)
+# q2 = session.query(Student.name).filter(Student.id <= 2)
+# result = q1.union(q2).all()
+
+# sql_stmt1 = select(User.name).where(User.id <= 2)
+# sql_stmt2 = select(Student.name).where(Student.id <= 4)
+# query_result = db_session.execute(sql_stmt1.union(sql_stmt2)).scalars()
+# for row in query_result:
+#     print(row)
+
+# sqlalchemy1.4 union_all
+# q1 = session.query(User.id, User.name)
+# q2 = session.query(Student.id.label('id'), Student.name.label('name'))
+# result = q1.union_all(q2).filter(User.id <= 2)
+# print(dict(result))
+
+# sql_stmt1 = select(User.name).where(User.id <= 2)
+# sql_stmt2 = select(Student.name).where(Student.id <= 4)
+# query_result = db_session.execute(sql_stmt1.union_all(sql_stmt2)).scalars()
+# for row in query_result:
+#     print(row)
+
+
 # select all scalars
 # result = db_session.execute(select(User)).scalars().all()  # [<1 name:rogersun>, <2 name:honeyhoney>, <3 name:haha>]
 # print(result)
@@ -359,3 +425,91 @@ insert_data2 = {'name': 'sql2_test2', 'password': 'pwd2'}
 # false 表示完全不更新 Python 中的对象
 # fetch 表示重新从数据库中加载一份对象
 # evaluate 表示在更新数据库的同时，也尽量在 Python 中的对象上使用同样的操作
+
+# delete
+# 插入测试数据
+# insert_stmt = insert(User).values([{'name': 'add', 'password': 'pwd1234'}, {'name': 'add', 'password': 'pwd1234'}])
+# insert_result = db_session.execute(insert_stmt)
+# db_session.flush()
+# db_session.commit()
+# print(type(insert_result))
+# print(insert_result.rowcount)
+# print(insert_result.is_insert)
+# print(insert_result.inserted_primary_key_rows)  # 2.x上返回None 这个bug会在未来版本修复
+
+# inserted_primary_key_rows 可用方式
+# conn = engine.connect()
+# ins = insert(User).values({'name': 'add', 'password': 'pwd1234'})
+# res = conn.execute(ins)
+# print(type(res))
+# print(res.inserted_primary_key_rows)
+
+# 抛异常 不能使用endswith 或 like这种 只能用 ==
+# del_stmt = delete(User).where(and_(User.name == 'add', User.password == 'pwd1234'))
+# del_result = db_session.execute(del_stmt)
+# db_session.commit()
+# print(type(del_result))
+# print(del_result.rowcount)
+
+
+# 结合select的删除
+# sel_stmt = select(User.id).where(and_(User.name == 'add', User.password.endswith('1234')))
+# sel_result = db_session.execute(sel_stmt).first()
+# for row in sel_result:
+#     print(row)
+# sql_stmt = delete(User).where(User.id.in_(sel_result))
+# query_result = db_session.execute(sql_stmt)
+# db_session.commit()
+# print(query_result)
+
+# CursorResult
+# all(), close(), columns(), fetchall(), fetchmany(), fetchone(), first(), freeze(), inserted_primary_key,
+# inserted_primary_key_rows, is_insert, keys(), last_inserted_params(), last_updated_params(), lastrow_has_defaults(),
+# lastrowid, mappings(), merge(), one(), one_or_none(), partitions(), postfetch_cols(), prefetch_cols(),
+# returned_defaults, returned_defaults_rows, returns_rows, rowcount, scalar(), scalar_one(), scalar_one_or_none(),
+# scalars(), splice_horizontally(), splice_vertically(), supports_sane_multi_rowcount(), supports_sane_rowcount(),
+# t, tuples(), unique(), yield_per()
+
+
+# connection
+# connection = engine.connect()
+# trans = connection.begin()
+# try:
+#     ins1 = insert(User).values({'name': 'add1', 'password': 'pwd1234'})
+#     ins2 = insert(User).values({'name': 'add2', 'password': 'pwd1234'})
+#     connection.execute(ins1)
+#     connection.execute(ins2)
+#     trans.commit()
+# except Exception as e:
+#     trans.rollback()
+#     raise e
+
+# 元数据表操作
+
+metadata = MetaData()  # 生成metadata
+
+user = Table(
+    'user',
+    metadata,
+    Column('id', Integer, primary_key=True),
+    Column('name', String(32)),
+    Column('password', String(64))
+)
+
+student = Table(
+    'student',
+    metadata,
+    Column('id', Integer, primary_key=True),
+    Column('name', String(32), nullable=False),
+    Column('gender', Enum('m', 'f'), nullable=False),
+    Column('date', DATE, nullable=False)
+)
+
+
+conn = engine.connect()
+# 插入
+# ins = user.insert().values({'name': 'metadata_add1', 'password': 'pwd1234'})
+ins = insert(user).values({'name': 'metadata_add2', 'password': 'pwd1234'})
+print(str(ins))
+ins_result = conn.execute(ins)
+print(ins_result.inserted_primary_key)

sqlalchemy_20/db_obj.py

@@ -50,3 +50,5 @@ student = Table(
     Column('gender', Enum('m', 'f'), nullable=False),
     Column('date', DATE, nullable=False)
 )
+
+metadata.create_all(engine)