用python简单实现类似thinkphp的针对Mysql操作的数据模型

摘自以前CI实现的商城系统，做APP时需要实现数据接口，便用python实现了。

假设有表tp_article

idtitletype1哈哈12图样涂森坡1

使用thinphp实现取出type为1的数据如下

M()->from(''tp_article'')->where('type=1')->select();

现通过python实现类似对mysql进行操作的封装

DB.select('*').fm('tp_article').where('type',1).all()

需要：django下的db模块

首先实现 mydb.py 文件，放于core目录下，实现模型类文件时需要import

from django.db import connectioncursor = connection.cursor()'''Simple function for one result sql'''#返回一条结果def fetchone(sql):    cursor.execute(sql)    try:        col_names = [row[0] for row in cursor.description]        rs = dict(zip(col_names,cursor.fetchone()))            except:        rs = {}                  return rs

<pre name="code" class="python">#返回多条结果

def fetchall(sql): cursor.execute(sql) try: col_names = [row[0] for row in cursor.description] data = cursor.fetchall() rs = [dict(zip(col_names,raw)) for raw in data] except: rs=[] return rs

然后就是实现模型类文件db_mysql.py

from core.mydb  import *class Db_mysql(object):    '''build sql'''    sql=''    options={}    history=[]        def select(self,fields):        select_list = fields.split(',')        self.options['select']=select_list        return self

    #实现from，因为from是python保留关键词，所以用fm代替

    def fm(self,table):                self.options['from'] = table        return self        def where(self,seg,*args):        '''        sql query of where tag        '''        try:            where_list=self.options['where']        except:            where_list=[]        if isinstance(seg,str):            try:                where_list.append({'key':seg,'val':args[0],'type':args[1]})            except:                where_list.append({'key':seg,'val':args[0],'type':False})        elif isinstance(seg,dict):            for key in seg.keys():                where_list.append({'key':key,'val':seg[key]})        self.options['where']= where_list        return self

    def where_in(self,key,val):        if not isinstance(self.options['where'],list):            self.options['where']=[]        self.options['where'].append({'key':key,'val':str(val),'type':'in'})        return self        def like(self,key,words):        if not isinstance(self.options['where'],list):            self.options['where']=[]        self.options['where'].append({'key':key,'val':str(words),'type':'like'})        return self        def join(self,table,on,type='left'):        self.options['join']= {'table':table,'on':on,'type':type}        return self        def limit(self,offset=0,size=0):        offset = int(offset)        size = int(size)        if size == 0:            size=offset            offset=0        self.options['limit']= {'offset':str(offset),'size':str(size)}        return self        def order(self,oby,desc='desc'):        self.options['order']={'order':str(oby),'desc':str(desc)}        return self    #组装sql就靠这个方法了     def combile_sql(self):        '''        combile select sql        '''        if not isinstance(self.options['select'],list):            self.options['select']=['*']                    self.sql=''.join(['select '])        length = len(self.options['select'])        for i in range(length):            fields = self.options['select'][i]            if i==length-1:                self.sql=''.join([self.sql,fields,' '])                break            self.sql=''.join([self.sql,fields,', '])        '''        combile from sql        '''                self.sql=''.join([self.sql,' from ',self.options['from'],' '])        '''        combile join sql        '''          try:            if isinstance(self.options['join'],dict):                join_str = self.options['join']        except:            pass        else:            self.sql=''.join([self.sql,join_str['type'],' join ',join_str['table'],' on ',join_str['on'],' '])        '''        combile where sql and where in sql        '''                        try:            where_list = self.options['where']        except:            where_list = []        else:            if len(where_list):                self.sql=''.join([self.sql,' where '])            count=0            for item in where_list:                if count is 0:                    segment = ' '                else:                    segment = ' AND '                count=count+1                if not item.get('type',False):                    self.sql=''.join([self.sql,segment,item['key'],'=',str(item['val'])])                elif item['type'] is 'in':                    self.sql=''.join([self.sql,segment,item['key'],' in (',str(item['val']),') '])                elif item['type'] is 'like':                    self.sql=''.join([self.sql,segment,item['key'],' like %',str(item['val']),'% '])                '''        combile order sql        '''        try:            order_dict = self.options['order']            if isinstance(order_dict,dict):                self.sql=''.join([self.sql,' order by ',order_dict['order'],' ',order_dict['desc']])           except:            pass                             '''        combile limit sql        '''        try:            self.sql=''.join([self.sql,' limit ',self.options['limit']['offset'],',',self.options['limit']['size']])            self.history.append(self.sql)            self.options = {}        except KeyError:            pass                return self   #查询操作，类似tp李的find    def get(self,table=False):        if not isinstance(table,bool):            self.options['from']        self.combile_sql()        rs={}        try:            rs = fetchone(self.sql)        except Exception as e:            print e            print self.sql        self.sql=''        return rs    #查询操作，类似tp里的select    def all(self,table=False):        if not isinstance(table,bool):            self.options['from']        self.combile_sql()        rs = []        try:            rs = fetchall(self.sql)        except Exception as e:            print e            print self.sql        self.sql=''        return rs    #修改操作    def update(self,table=False,*args):                if not isinstance(table,bool):            self.sql=''.join(['update ',table,' set '])        else:            return False

<span style="white-space:pre"></span>#判断方法接收的参数是字符串还是字典，做不同处理        if isinstance(args[0],str):            if isinstance(args[1],str):                val = ''.join(["'",args[1],"'"])            else:                val = str(args[1])            self.sql = ''.join([self.sql,args[0],'=',val,' '])        elif isinstance(args[0],dict):            count=0            for key in args[0].keys():                if count is 0:                    segment = ' '                else:                    segment = ','                if isinstance(args[0][key],str):                    val = ''.join(["'",args[0][key],"'"])                else:                    val = str(args[0][key])                self.sql = ''.join([self.sql,segment,key,'=',val,' '])                count = count+1        '''        combile where sql and where in sql        '''                try:            where_list = self.options['where']        except:            where_list = []        else:            if len(where_list):                self.sql=''.join([self.sql,' where '])            count=0            for item in where_list:                if count is 0:                    segment = ' '                else:                    segment = ' AND '                count=count+1                if not item.get('type',False):                    self.sql=''.join([self.sql,segment,item['key'],'=',str(item['val'])])                elif item['type'] is 'in':                    self.sql=''.join([self.sql,segment,item['key'],' in (',str(item['val']),') '])                elif item['type'] is 'like':                    self.sql=''.join([self.sql,segment,item['key'],' like %',str(item['val']),'% '])        '''        combile where sql and where in sql        '''          rs = fetchone(self.sql)        self.options = {}        self.sql=''        return rs

    #插入操作    def insert(self,table=False,seg={}):                if not isinstance(table,bool):            self.sql=''.join(['insert into ',table,' '])        else:            return False        if isinstance(seg,dict):            count=0            keystr=''            valstr=''            for key in seg.keys():                if count is 0:                    segment = ''                else:                    segment = ','                keystr = ''.join([keystr,segment,key])                if isinstance(seg[key],str):                    val = ''.join(["'",seg[key],"'"])                else:                    val = str(seg[key])                valstr = ''.join([valstr,segment,val])         self.sql=''.join([self.sql,'(',keystr,')',' values ','(',valstr,')'])        rs = fetchone(self.sql)        self.options = {}        self.sql=''        return rs

    #删除操作    def delete(self,table=False):                if not isinstance(table,bool):            self.sql=''.join(['delete from ',table,' '])        else:            return False        '''        combile where sql and where in sql        '''                try:            where_list = self.options['where']        except:            where_list = []        else:            if len(where_list):                self.sql=''.join([self.sql,' where '])            count=0            for item in where_list:                if count is 0:                    segment = ' '                else:                    segment = ' AND '                count=count+1                if not item.get('type',False):                    self.sql=''.join([self.sql,segment,item['key'],'=',str(item['val'])])                elif item['type'] is 'in':                    self.sql=''.join([self.sql,segment,item['key'],' in (',str(item['val']),') '])                elif item['type'] is 'like':                    self.sql=''.join([self.sql,segment,item['key'],' like %',str(item['val']),'% '])        '''        combile where sql and where in sql        '''          rs = fetchone(self.sql)        self.options = {}        self.sql=''        return rs#测试DB = Db_mysql()DB.select('attr_id,attr_name').fm('hr_attribute').where('attr_type',0).where_in('attr_id','3,4,6').join('goods as g','g.id=a.id','left').order('attr_id').limit(3,5);DB.get()

经测试，没有什么大问题，如果有问题建议请告诉我哦