Sure, here is a modified `DatabaseManager` class that allows performing CRUD operations in bulk and commiting them in a single transaction. The class receives a list of data as the data source.
```python
from sqlalchemy import create_engine, MetaData, Table, Column, Integer, String
from sqlalchemy.orm import sessionmaker

class DatabaseManager:

    def __init__(self, database_url):
        self.engine = create_engine(database_url)
        self.metadata = MetaData(bind=self.engine)
        self.session_factory = sessionmaker(bind=self.engine)

    def execute_query(self, query):
        with self.session_factory() as session:
            result = session.execute(query)
            return result.fetchall()

    def create_table(self, table_name, columns):
        table = Table(table_name, self.metadata, *[
            Column(name, dtype) for name, dtype in columns
        ])
        table.create()

    def insert_data(self, table_name, data, columns, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        if not bulk:
            data_dict = dict(zip(columns, data))
            new_row = table.insert().values(**data_dict)
            with self.session_factory() as session:
                session.execute(new_row)
        else:
            data_dicts = [dict(zip(columns, row)) for row in data]
            new_rows = table.insert().values(data_dicts)
            with self.session_factory().begin() as session:
                session.execute(new_rows)

    def select_data(self, table_name, columns=None, condition=None, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        select_query = table.select()
        if columns is not None:
            select_query = select_query.with_only_columns([table.c[name] for name in columns])
        if condition is not None:
            select_query = select_query.where(condition)
        with self.session_factory() as session:
            if not bulk:
                result = session.execute(select_query)
                return result.fetchone()
            else:
                result = session.execute(select_query)
                return result.fetchall()

    def update_data(self, table_name, column, value, condition, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        update_query = table.update().where(condition).values({column: value})
        with self.session_factory() as session:
            if not bulk:
                session.execute(update_query)
            else:
                session.execute(update_query)

    def delete_data(self, table_name, condition, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        delete_query = table.delete().where(condition)
        with self.session_factory() as session:
            if not bulk:
                session.execute(delete_query)
            else:
                session.execute(delete_query)

    def commit(self):
        with self.session_factory().begin() as session:
            session.commit()
```
Here's an example of how to use this modified `DatabaseManager` class to perform CRUD operations in bulk:
```python
db_manager = DatabaseManager('postgresql://myuser:mypassword@localhost:5432/mydatabase')
table_name = 'my_table'
columns = ['id', 'name']
data = [
    [1, 'John'],
    [2, 'Jane'],
    [3, 'Bob']
]

# Bulk insert
db_manager.insert_data(table_name, data, columns, bulk=True)

# Bulk update
db_manager.update_data(table_name, 'name', 'Johnny', 'id IN (1, 2, 3)', bulk=True)

# Bulk delete
db_manager.delete_data(table_name, 'id IN (1, 2, 3)', bulk=True)

# Commit all changes in one transaction
db_manager.commit()
```
물론, 여기에는 CRUD 작업을 대량으로 수행하고 단일 트랜잭션으로 커밋할 수 있는 수정된 `DatabaseManager` 클래스가 있습니다. 이 클래스는 데이터 리스트를 데이터 소스로 받습니다.
```python
에서 create_engine, 메타데이터, 테이블, 열, 정수, 문자열을 가져옵니다.
sqlalchemy.orm에서 세션메이커를 가져옵니다.

데이터베이스관리자 클래스:

    def __init__(self, database_url):
        self.engine = create_engine(database_url)
        self.metadata = 메타데이터(바인드=self.엔진)
        self.session_factory = 세션메이커(바인드=self.엔진)

    def execute_query(self, query):
        self.session_factory()를 세션으로 사용합니다:
            결과 = 세션.실행(쿼리)
            return result.fetchall()

    def create_table(self, table_name, columns):
        table = Table(table_name, self.metadata, *[[
            Column(name, dtype) for name, dtype in columns
        ])
        table.create()

    def insert_data(self, table_name, data, columns, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        벌크가 아닌 경우:
            data_dict = dict(zip(columns, data))
            new_row = table.insert().values(**data_dict)
            self.session_factory()를 세션으로 사용합니다:
                session.execute(new_row)
        else:
            data_dicts = [dict(zip(열, 행)) for row in data]
            new_rows = table.insert().values(data_dicts)
            self.session_factory().begin()을 세션으로 사용합니다:
                session.execute(new_rows)

    def select_data(self, table_name, columns=None, condition=None, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        select_query = table.select()
        열이 None이 아닌 경우:
            select_query = select_query.with_only_columns([table.c[name] for name in columns])
        조건이 None이 아닌 경우
            select_query = select_query.where(condition)
        self.session_factory()를 세션으로 사용합니다:
            벌크가 아닌 경우
                result = session.execute(select_query)
                return result.fetchone()
            else:
                결과 = 세션.실행(select_query)
                return result.fetchall()

    def update_data(self, table_name, column, value, condition, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        update_query = table.update().where(condition).values({column: value})
        self.session_factory()를 세션으로 사용합니다:
            벌크가 아니라면
                세션.실행(업데이트_쿼리)
            else:
                세션.실행(업데이트_쿼리)

    def delete_data(self, table_name, condition, bulk=False):
        table = Table(table_name, self.metadata, autoload=True)
        delete_query = table.delete().where(condition)
        self.session_factory()를 세션으로 사용합니다:
            벌크가 아니라면
                session.execute(delete_query)
            else:
                세션.실행(삭제_쿼리)

    def commit(self):
        with self.session_factory().begin() as session:
            session.commit()
```
다음은 이 수정된 `DatabaseManager` 클래스를 사용하여 CRUD 작업을 대량으로 수행하는 방법에 대한 예제입니다:
```python
db_manager = DatabaseManager('postgresql://myuser:mypassword@localhost:5432/mydatabase')
table_name = 'my_table'
columns = ['id', 'name']
data = [
    [1, 'John'],
    [2, 'Jane'],
    [3, 'Bob']
]

# 대량 삽입
db_manager.insert_data(table_name, data, columns, bulk=True)

# 대량 업데이트
db_manager.update_data(table_name, 'name', 'Johnny', 'id IN (1, 2, 3)', bulk=True)

# 대량 삭제
db_manager.delete_data(table_name, 'id IN (1, 2, 3)', bulk=True)

# 모든 변경 사항을 하나의 트랜잭션으로 커밋
db_manager.commit()
```