使用sqlalchemy-gbasedbt连接GBase 8s数据库

测试环境：

• 操作系统：CentOS 7.9 64-bit
• 数据库版本：GBase8sV8.8_AEE_3.0.0_1，对应的CSDK版本为3.0.0_1

1，确认安装python3

确认已经安装python3和python3-devel

[root@localhost test]# python3 -V
Python 3.6.8

如果没有安装，建议使用yum install python3来安装。
升级pip的版本

[root@localhost test]# python3 -m pip install --upgrade --force-reinstall pip
WARNING: Running pip install with root privileges is generally not a good idea. Try `__main__.py install --user` instead.
Collecting pip
  Downloading https://files.pythonhosted.org/packages/a4/6d/6463d49a933f547439d6b5b98b46af8742cc03ae83543e4d7688c2420f8b/pip-21.3.1-py3-none-any.whl (1.7MB)
    100% |████████████████████████████████| 1.7MB 235kB/s
Installing collected packages: pip
Successfully installed pip-21.3.1
[root@localhost test]# pip3 list
WARNING: pip is being invoked by an old script wrapper. This will fail in a future version of pip.
Please see https://github.com/pypa/pip/issues/5599 for advice on fixing the underlying issue.
To avoid this problem you can invoke Python with '-m pip' instead of running pip directly.
Package    Version
---------- -------
pip        21.3.1
setuptools 39.2.0

2，安装GBase 8s数据库连接工具（CSDK）

可以直接下载免安装版本的CSDK驱动：
链接：https://pan.baidu.com/s/1s9EW3VoRznlj6uDHubIEtg?pwd=ejfb
提取码：ejfb
解压到指定目录/opt下，生成/opt/gbase8s-odbc-driver目录

[root@localhost test]# ll
总用量 35188
-rw-r--r--. 1 root root 36029237 3月  11 20:52 GBase8s_3.0.0_1-Linux64-ODBC-Driver.tar.gz
[root@localhost test]# tar -zxf GBase8s_3.0.0_1-Linux64-ODBC-Driver.tar.gz -C /opt/
[root@localhost test]# cd /opt/
[root@localhost opt]# ll
总用量 4
drwxr-xr-x. 20 gbasedbt gbasedbt 4096 3月  10 15:14 gbase
drwxrwxr-x.  9     1001     1003   88 12月 13 2020 gbase8s-odbc-driver
drwxr-xr-x.  2 root     root        6 10月 31 2018 rh

创建必须的环境变量，并使环境生效

export GBASEDBTDIR=/opt/gbase8s-odbc-driver
export CSDK_HOME=/opt/gbase8s-odbc-driver
export PATH=$GBASEDBTDIR/bin:$PATH
export LD_LIBRARY_PATH=$GBASEDBTDIR/lib:$GBASEDBTDIR/lib/cli:$GBASEDBTDIR/lib/esql:$LD_LIBRARY_PATH

创建sqlhosts配置文件

[root@localhost test]# vi /opt/gbase8s-odbc-driver/etc/sqlhosts
[root@localhost test]# more /opt/gbase8s-odbc-driver/etc/sqlhosts
gbase01 onsoctcp a02.gbasedbt.com 9088

3，安装sqlalchemy-gbasedbt

3.1, 在线安装sqlalchemy-gbasedbt

确认python3、python3-devel和gcc均已经安装，CSDK也已经安装以及环境变量已经配置的情况下，可直连网络的情况下，可使用pip3 install sqlalchemy-gbasedbt直接安装

[root@localhost test]# pip3 install sqlalchemy-gbasedbt
Collecting sqlalchemy-gbasedbt
  Using cached sqlalchemy_gbasedbt-0.2.4-py3-none-any.whl (10 kB)
Collecting DbtPy
  Using cached DbtPy-3.0.5.4.tar.gz (162 kB)
  Preparing metadata (setup.py) ... done
Requirement already satisfied: sqlalchemy in /usr/local/lib64/python3.6/site-packages (from sqlalchemy-gbasedbt) (1.4.46)
Requirement already satisfied: greenlet!=0.4.17 in /usr/local/lib64/python3.6/site-packages (from sqlalchemy->sqlalchemy-gbasedbt) (2.0.2)
Requirement already satisfied: importlib-metadata in /usr/local/lib/python3.6/site-packages (from sqlalchemy->sqlalchemy-gbasedbt) (4.8.3)
Requirement already satisfied: typing-extensions>=3.6.4 in /usr/local/lib/python3.6/site-packages (from importlib-metadata->sqlalchemy->sqlalchemy-gbasedbt) (4.1.1)
Requirement already satisfied: zipp>=0.5 in /usr/local/lib/python3.6/site-packages (from importlib-metadata->sqlalchemy->sqlalchemy-gbasedbt) (3.6.0)
Using legacy 'setup.py install' for DbtPy, since package 'wheel' is not installed.
Installing collected packages: DbtPy, sqlalchemy-gbasedbt
    Running setup.py install for DbtPy ... done
Successfully installed DbtPy-3.0.5.4 sqlalchemy-gbasedbt-0.2.4

将同时安装依赖包：sqlalchemy、greenlet、importlib-metadata、typing-extensions、zipp和DbtPy，安装后的pip3列表如下：

[root@localhost test]# pip3 list
Package             Version
------------------- -------
DbtPy               3.0.5.4
greenlet            2.0.2
importlib-metadata  4.8.3
pip                 21.3.1
setuptools          39.2.0
SQLAlchemy          1.4.46
sqlalchemy-gbasedbt 0.2.4
typing_extensions   4.1.1
zipp                3.6.0

4，编写测试Demo，执行测试

测试demo文件

#!/usr/bin/env python3
# Filename: testSqlalchemy_gbasedbt

from sqlalchemy import MetaData, Table, Column, String, create_engine
from sqlalchemy.dialects import registry
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

registry.register("gbasedbt", "sqlalchemy_gbasedbt.dbtdb", "GBasedbtDialect")

# 创建对象的基类:
Base = declarative_base()

# 定义User对象:
class User(Base):
    # 表的名字:
    __tablename__ = 'user'

    # 表的结构:
    id = Column(String(20), primary_key=True)
    name = Column(String(20))

# 初始化数据库连接:
# ConStr = 'gbasedbt://<username>:<password>@<host name>:<port number>/<databasename>;SERVER=<server name>'
ConStr = 'gbasedbt://gbasedbt:GBase123@a02.gbasedbt.com:9088/testdb;SERVER=gbase01;DB_LOCALE=zh_CN.utf8;CLIENT_LOCALE=zh_CN.utf8;DELIMIDENT=y'
engine = create_engine(ConStr)

# 创建对象
Base.metadata.create_all(engine)

# 创建DBSession类型:
DBSession = sessionmaker(bind=engine)

# 创建session对象:
session = DBSession()

# 创建新User对象:
new_user = User(id='2', name='测试用户')
# 添加到session:
session.add(new_user)
# 提交即保存到数据库:
session.commit()
# 关闭session:
session.close()

# 创建Session:
session = DBSession()
# 创建Query查询，filter是where条件，最后调用one()返回唯一行，如果调用all()则返回所有行:
user = session.query(User).filter(User.id=='2').one()
# 打印类型和对象的name属性:
print('type:', type(user))
print('name:', user.name)
# 关闭Session:
session.close()

测试结果：

[root@localhost test]# ./testSqlalchemy_gbasedbt.py
type: <class '__main__.User'>
name: 测试用户