Python带动态参数功能的sqlite工具类

本文实例讲述了Python带动态参数功能的sqlite工具类。分享给大家供大家参考，具体如下：

最近在弄sqlite和python

在网上参考各教程后，结合以往java jdbc数据库工具类写出以下python连接sqlite的工具类

写得比较繁琐 主要是想保留一种类似java的Object…args动态参数写法 并兼容数组/list方式传递不定个数参数 并且返回值是List形式 dict字典 以便和JSON格式互相转换

在python中有一些区别 经过该工具类封装之后可以有以下用法：

db.executeQuery("s * f t w id=? and name=?", "id01", "name01");//动态参数形式
db.executeQuery("s * f t w id=? and name=?", ("id01", "name01"));//tuple元组式 等价上面 括号可省略
db.executeQuery("s * f t w id=? and name=?", ["id01", "name01"]);//list数组形式

完整Python代码如下：

#!/usr/bin/python
#-*- coding:utf-8 -*-  
import sqlite3
import os 
#
# 连接数据库帮助类
# eg:
#  db = database()
#  count,listRes = db.executeQueryPage("select * from student where id=? and name like ? ", 2, 10, "id01", "%name%")
#  listRes = db.executeQuery("select * from student where id=? and name like ? ", "id01", "%name%")
#  db.execute("delete from student where id=? ", "id01")
#  count = db.getCount("select * from student ")
#  db.close()
#
class database :
  dbfile = "sqlite.db"
  memory = ":memory:"
  conn = None
  showsql = True
  def __init__(self):
    self.conn = self.getConn()
  #输出工具
  def out(self, outStr, *args):
    if(self.showsql):
      for var in args:
        if(var):
          outStr = outStr + ", " + str(var)
      print("db. " + outStr)
    return 
  #获取连接
  def getConn(self):
    if(self.conn is None):
      conn = sqlite3.connect(self.dbfile)
      if(conn is None):
        conn = sqlite3.connect(self.memory)
      if(conn is None):
        print("dbfile : " + self.dbfile + " is not found && the memory connect error ! ")
      else:
        conn.row_factory = self.dict_factory #字典解决方案
        self.conn = conn
      self.out("db init conn ok ! ")
    else:
      conn = self.conn
    return conn
  #字典解决方案
  def dict_factory(self, cursor, row): 
    d = {} 
    for idx, col in enumerate(cursor.description): 
      d[col[0]] = row[idx] 
    return d
  #关闭连接
  def close(self, conn=None):
    res = 2
    if(not conn is None):
      conn.close()
      res = res - 1
    if(not self.conn is None):
      self.conn.close()
      res = res - 1
    self.out("db close res : " + str(res))
    return res
  #加工参数tuple or list 获取合理参数list
  #把动态参数集合tuple转为list 并把单独的传递动态参数list从tuple中取出作为参数
  def turnArray(self, args):
    #args (1, 2, 3) 直接调用型 exe("select x x", 1, 2, 3)
    #return [1, 2, 3] <- list(args)
    #args ([1, 2, 3], ) list传入型 exe("select x x",[ 1, 2, 3]) len(args)=1 && type(args[0])=list
    #return [1, 2, 3]
    if(args and len(args) == 1 and (type(args[0]) is list) ):
      res = args[0]
    else:
      res = list(args)
    return res
  #分页查询 查询page页 每页num条 返回 分页前总条数 和 当前页的数据列表 count,listR = db.executeQueryPage("select x x",1,10,(args))
  def executeQueryPage(self, sql, page, num, *args):
    args = self.turnArray(args)
    count = self.getCount(sql, args)
    pageSql = "select * from ( " + sql + " ) limit 5 offset 0 "
    #args.append(num)
    #args.append(int(num) * (int(page) - 1) )
    self.out(pageSql, args) 
    conn = self.getConn()
    cursor = conn.cursor()
    listRes = cursor.execute(sql, args).fetchall()
    return (count, listRes)  
  #查询列表array[map] eg: [{'id': u'id02', 'birth': u'birth01', 'name': u'name02'}, {'id': u'id03', 'birth': u'birth01', 'name': u'name03'}]
  def executeQuery(self, sql, *args):
    args = self.turnArray(args)
    self.out(sql, args) 
    conn = self.getConn()
    cursor = conn.cursor()
    res = cursor.execute(sql, args).fetchall()
    return res  
  #执行sql或者查询列表 并提交
  def execute(self, sql, *args):
    args = self.turnArray(args)
    self.out(sql, args) 
    conn = self.getConn()
    cursor = conn.cursor()
    #sql占位符 填充args 可以是tuple(1, 2)(动态参数数组) 也可以是list[1, 2] list(tuple) tuple(list)
    res = cursor.execute(sql, args).fetchall()
    conn.commit()
    #self.close(conn)
    return res  
  #查询列名列表array[str] eg: ['id', 'name', 'birth']
  def getColumnNames(self, sql, *args):
    args = self.turnArray(args)
    self.out(sql, args) 
    conn = self.getConn()
    if(not conn is None):
      cursor = conn.cursor()
      cursor.execute(sql, args)
      res = [tuple[0] for tuple in cursor.description]
    return res  
  #查询结果为单str eg: 'xxxx'
  def getString(self, sql, *args):
    args = self.turnArray(args)
    self.out(sql, args) 
    conn = self.getConn()
    cursor = conn.cursor()
    listRes = cursor.execute(sql, args).fetchall()
    columnNames = [tuple[0] for tuple in cursor.description]
    #print(columnNames)
    res = ""
    if(listRes and len(listRes) >= 1):
      res = listRes[0][columnNames[0]]
    return res   
  #查询记录数量 自动附加count(*) eg: 3
  def getCount(self, sql, *args):
    args = self.turnArray(args)
    sql = "select count(*) cc from ( " + sql + " ) "
    resString = self.getString(sql, args)  
    res = 0   
    if(resString):
      res = int(resString)
    return res
####################################测试
def main():
  db = database()
  db.execute(
    ''' 
    create table if not exists student(
      id   text primary key,
      name  text not null,
      birth  text 
    )
    ''' 
  )
  for i in range(10):
    db.execute("insert into student values('id1" + str(i) + "', 'name1" + str(i) + "', 'birth1" + str(i) + "')")
  db.execute("insert into student values('id01', 'name01', 'birth01')")
  db.execute("insert into student values('id02', 'name02', 'birth01')")
  db.execute("insert into student values('id03', 'name03', 'birth01')")
  print(db.getColumnNames("select * from student"))
  print(db.getCount("select * from student " ))
  print(db.getString("select name from student where id = ? ", "id02" ))
  print(db.executeQuery("select * from student where 1=? and 2=? ", 1, 2 ))
  print(db.executeQueryPage("select * from student where id like ? ", 1, 5, "id0%"))
  db.execute("update student set name='nameupdate' where id = ? ", "id02")
  db.execute("delete from student where id = ? or 1=1 ", "id01")
  db.close()
if __name__ == '__main__':
  main()

希望本文所述对大家Python程序设计有所帮助。