【pandas】pandas 写入postgresql 比较快的方法

一种是导入sqlalchemy包，另一种是导入psycopg2包。
具体用法如下（此处以postgre数据库举例）
postgresql://用户名:密码@host:port/db_name

engine = create_engine("oracle://user:pwd@***:***/racdb", echo=False)
# 初始化引擎
engine = create_engine('postgresql+psycopg2://' + pg_username + ':' + pg_password + '@' + pg_host + ':' + str(pg_port) + '/' + pg_database)

#一种是导入sqlalchemy包，另一种是导入psycopg2包。
#具体用法如下（此处以postgre数据库举例）
#postgresql://用户名:密码@host:port/db_name

#engine = create_engine("oracle://user:pwd@***:***/racdb", echo=False)
# 初始化引擎
#engine = create_engine('postgresql+psycopg2://' + pg_username + ':' + pg_password + '@' + pg_host + ':' + str(pg_port) + '/' + pg_database)


def write_to_table(df, table_name, schema_name, if_exists='fail'):
    import io
    import pandas as pd
    from sqlalchemy import create_engine
    db_engine = create_engine('postgresql://***:***@***:***/***')# 初始化引擎
    string_data_io = io.StringIO()
    df.to_csv(string_data_io, sep='|', index=False)
    pd_sql_engine = pd.io.sql.pandasSQL_builder(db_engine)
    table = pd.io.sql.SQLTable(table_name, pd_sql_engine, frame=df,
                               index=False, if_exists=if_exists,schema = schema_name)
    table.create()
    string_data_io.seek(0)
    string_data_io.readline()  # remove header
    with db_engine.connect() as connection:
        with connection.connection.cursor() as cursor:
            copy_cmd = "COPY {}.{} FROM STDIN HEADER DELIMITER '|' CSV".format(table_name, schema_name)
            cursor.copy_expert(copy_cmd, string_data_io)
        connection.connection.commit()

至此完成！！！