sqlalchemy根据数据库结构生成映射的实体

# !/usr/bin/python
# -*- coding: UTF-8 -*-

from sqlalchemy import *
from sqlalchemy.orm import sessionmaker
from sqlalchemy.orm import Session
from sqlalchemy.ext.declarative import declarative_base

# 创建对象的基类:
Base = declarative_base()

class PTable(Base):
    
    __tablename__ = 'tables'

    table_catalog = Column(String(512))               #
    table_schema = Column(String(64))                 #
    table_name = Column(String(64), primary_key=True)
    table_type = Column(String(64))                   #
    engine = Column(String(64))                       #
    version = Column(BigInteger)                      #
    row_format = Column(String(10))                   #
    table_rows = Column(BigInteger)                   #
    avg_row_length = Column(BigInteger)               #
    data_length = Column(BigInteger)                  #
    max_data_length = Column(BigInteger)              #
    index_length = Column(BigInteger)                 #
    data_free = Column(BigInteger)                    #
    auto_increment = Column(BigInteger)               #
    create_time = Column(Date)                        #
    update_time = Column(Date)                        #
    check_time = Column(Date)                         #
    table_collation = Column(String(32))              #
    checksum = Column(BigInteger)                     #
    create_options = Column(String(2048))             #
    table_comment = Column(String(2048))              #

class PColumn(Base):
    
    __tablename__ = 'columns'

    table_schema = Column(String(255))
    table_name = Column(String(255))
    column_name = Column(String(255), primary_key=True)
    data_type = Column(String(255))
    character_maximum_length = Column(String(255)) #字符类型时，字段长度
    column_key = Column(String(255)) #PRI为主键，UNI为unique，MUL是什么意思？
    column_comment = Column(String(255)) #字段说明
    extra = Column(String(255)) #'auto_increment'

dic = {}
dic["tinyint"] = "Boolean"
dic["smallint"] = "SmallInteger"
dic["mediumint"] = "Integer"
dic["int"] = "Integer"
dic["integer"] = "Integer"
dic["bigint"] = "BigInteger"
dic["float"] = "Float"
dic["double"] = "Numeric"
dic["decimal"] = "Numeric"
dic["date"] = "Date"
dic["time"] = "Time"
dic["year"] = "Integer"
dic["datetime"] = "Date"
dic["timestamp"] = "Date"
dic["char"] = "String"
dic["varchar"] = "String"
dic["tinyblob"] = "String"
dic["tinytext"] = "String"
dic["blob"] = "String"
dic["text"] = "String"
dic["mediumblob"] = "LargeBinary"
dic["mediumtext"] = "String"
dic["longblob"] = "LargeBinary"
dic["longtext"] = "String"


session = None;

def open(host,port,db,user,pwd) :
    url = 'mysql+mysqlconnector://%s:%s@%s:%d/%s' % (user,pwd,host,port,db)
    engine = create_engine(url)
    DbSession = sessionmaker(bind=engine)
    session = DbSession()

    return session

def close() :
    session.close()

def generate_db(db_name) :
    tq = session.query(PTable)
    ts = tq.filter(PTable.table_schema==db_name).all()

    for t in ts:
        generate_table(t.table_name,t.table_comment)

def generate_table(table_name,memoto) : 

    print ""
    print "#%s" % memoto
    print "class %s(Base) : " % table_name
    print ""
    print "    __tablename__ = '%s'" % table_name
    print ""
    
    cq = session.query(PColumn)
    cs = cq.filter(PColumn.table_name== table_name ).all()

    for c in cs:
        item = generate_column(c)
        print item 

def generate_column(c) : 
    item = "    " + c.column_name.lower()+" = Column("+dic[c.data_type]
    if c.character_maximum_length != None :
        item = item + "(%d)" % c.character_maximum_length
    if c.column_key == "PRI":
        item = item + ",primary_key=True"

    item = item + ")"
    item = item.ljust(60)

    if c.column_comment != None :
        item = item +"# "+c.column_comment
    return item

session = open("127.0.0.1",3306,"information_schema","root","xxx")
generate_db("netsharp")
close()

生成的结果如下

#
class sys_job(Base) :

    __tablename__ = 'sys_job'

    group_name = Column(String(50))                         #
    cron = Column(String(50))                               #
    cron_description = Column(String(500))                  #
    description = Column(String(500))                       #
    java_type = Column(String(500))                         #
    par = Column(String(200))                               #
    status = Column(Integer)                                #
    resource_node_id = Column(Integer)                      #
    code = Column(String(50))                               #
    name = Column(String(200))                              #
    memoto = Column(String(1000))                           #
    id = Column(Integer,primary_key=True)                   #
    creator_id = Column(Integer)                            #
    creator = Column(String(50))                            #
    create_time = Column(Date)                              #
    updator_id = Column(Integer)                            #
    updator = Column(String(50))                            #
    update_time = Column(Date)                              #
    ts = Column(Date)                                       #
    job_group = Column(String(50))                          #
    cron_expression = Column(String(50))                    #

#
class sys_job_log(Base) :

    __tablename__ = 'sys_job_log'

    group_name = Column(String(50))                         #
    java_type = Column(String(500))                         #
    operation = Column(String(50))                          #
    timed = Column(BigInteger)                              #
    code = Column(String(50))                               #
    name = Column(String(200))                              #
    memoto = Column(String(1000))                           #
    id = Column(Integer,primary_key=True)                   #
    creator_id = Column(Integer)                            #
    creator = Column(String(50))                            #
    create_time = Column(Date)                              #
    updator_id = Column(Integer)                            #
    updator = Column(String(50))                            #
    update_time = Column(Date)                              #
    ts = Column(Date)                                       #
    job_group = Column(String(50))                          #
    operation_date = Column(Date)                           #