用到正则，函数，排序等基础知识，可以用来练练手
import re
tableName = 'staff_table'
# 1.可进行模糊查询，语法至少支持下面3种查询语法:
# 2.可创建新员工纪录，以phone做唯一键(即不允许表里有手机号重复的情况)，staff_id需自增
# 3.可删除指定员工信息纪录，输入员工id，即可删除
# 4.可修改员工信息，语法如下:
# find name,age from staff_table where age > 22
# find * from staff_table where dept = "IT"
# find * from staff_table where enroll_date like "2013"
# 语法: add staff_table Alex Li,25,134435344,IT,2015‐10‐29
# 语法: del from staff_table where staff_id=3
# UPDATE staff_table SET dept="Market" WHERE dept = "IT" 把所有dept=IT的纪录的dept改成Market
# UPDATE staff_table SET age=25 WHERE name = "Alex Li" 把name=Alex Li的纪录的年龄改成25
def fuzzyQuery(sql):
print('begin query')
r = re.search('find\s*(.*)\s*from\s*(.*)\swhere\s*(.*)', sql)
conditions = r.groups()
if not conditions or len(conditions) != 3:
print('Sql error')
if conditions[1] != tableName:
print('Table name error')
findColumns = conditions[0]
whereSql = conditions[2]
ids = getIdByWhere(whereSql)
print('查询出了%s条' % (len(ids),))
print('result:')
for id in ids:
if findColumns.strip() == '*':
print(idDetailMap.get(id))
else:
printResult = ''
findColumnsList = findColumns.split(',')
for column in findColumnsList:
columnIndex = columnIndexMap.get(column.strip())
if not columnIndex:
raise Exception('find columns error')
else:
printResult += str(idDetailMap.get(id)[columnIndex])
print(printResult)
def addInfo(sql):
print('begin add')
r = re.search('add\s*%s\s*(.*)' % (tableName,), sql)
addInfo = r.groups()
if addInfo:
addInfoList = addInfo[0].split(',')
if len(addInfoList) != len(columnIndexMap) - 1:
raise ('add info error')
phone = addInfoList[columnIndexMap.get('phone') - 1]
existsPhones = [info[columnIndexMap.get('phone')] for info in infoList]
if phone in existsPhones:
raise Exception('电话不可重复')
maxId = max([int(info[columnIndexMap.get('staff_id')]) for info in infoList]) if infoList else 0
newId = maxId + 1
f.write('\n' + str(newId) + ',' + addInfo[0])
f.flush()
print('新增一条信息')
# 修改文件后更新相关数据
getEmployeeInfo()
def delInfo(sql):
print('begin del')
r = re.search('del\s*from\s*%s\s*where\s*(.*)' % (tableName,), sql)
ids = getIdByWhere(r.groups()[0])
for id in ids:
del idDetailMap[id]
updateFile()
print('删除了%s条数据'%(len(ids),))
def updateFile():
f.seek(0)
f.truncate()
sortedIdDetailMap = sorted(idDetailMap.items(), key=lambda x: int(x[0]))
for k in sortedIdDetailMap:
row = ",".join(k[1])
f.write("%s\n" % row)
f.flush()
getEmployeeInfo()
def updateInfo(sql):
print('begin update')
r = re.search('update\s*%s\sset\s*(.*)\s*where\s*(.*)' % (tableName,), sql).groups()
ids = getIdByWhere(r[1])
updateColumn = r[0].split('=')[0].strip()
if updateColumn == 'staff_id':
raise Exception('staff_id 不能被修改')
updateColumnValue = str(eval(r[0].split('=')[1].strip()))
for id in ids:
idDetailMap[id][columnIndexMap.get(updateColumn)] = updateColumnValue
updateFile()
print('更新了%s条数据' % (len(ids)))
def getIdByWhere(whereSql):
'''
目前只考虑一个条件
:param whereSql:
:return:
'''
r = re.search('(\S*)\s*(=|<=|>=|<|>|like)\s*(.*)', whereSql)
group = r.groups()
if not group or len(group) < 3:
raise Exception('where sql error')
column = group[0]
columeIndex = columnIndexMap.get(column)
if columeIndex is None:
raise Exception(column, 'not exists')
value = group[2]
if group[1] == 'like':
operation = ' in '
columeValues = [i[0] for i in infoList if eval('%s%s%s' % (
value, operation,
i[columeIndex] if i[columeIndex].isdigit() else '"' + i[columeIndex].lower() + '"'))]
else:
operation = ' == ' if group[1] == '=' else group[1]
columeValues = [i[0] for i in infoList if eval('%s%s%s' % (
i[columeIndex] if i[columeIndex].isdigit() else '"' + i[columeIndex].lower() + '"', operation, value))]
print('found staff_id: %s' % (str(columeValues),))
return columeValues
# 获取员工信息
def getEmployeeInfo():
global infoList, f, idDetailMap
f.seek(0)
rawData = f.readlines()
infoList = []
idDetailMap = {}
for item in rawData:
rowData = item.rstrip('\n').split(',')
if rowData:
infoList.append(rowData)
idDetailMap[rowData[columnIndexMap.get('staff_id')]] = rowData
print(infoList)
return infoList, idDetailMap
infoFile = "employeeInfo.txt"
f = open(infoFile, 'r+', encoding='utf-8')
columnIndexMap = {"staff_id": 0, "name": 1, "age": 2, "phone": 3, "dept": 4, "enroll_date": 5}
infoList, idDetailMap = getEmployeeInfo()
try:
while True:
try:
sql = input('sql:')
sql = sql.strip().lower()
if sql.startswith('find'):
fuzzyQuery(sql)
elif sql.startswith('add'):
addInfo(sql)
elif sql.startswith('del'):
delInfo(sql)
elif sql.startswith('update'):
updateInfo(sql)
elif sql == 'quit':
print('quit')
f.close()
break
else:
print('sql invalid')
continue
except Exception as e:
print('error msg:', e.__str__())
finally:
if f:
f.close()
employeeInfo.txt
1,Alex Li,22,13651054608,IT,2013‐04‐01
2,Jack Wang,28,13451024608,HR,2015‐01‐07
4,Mack Qiao,44,15653354208,Sales,2016‐02‐01
5,Rachel Chen,23,13351024606,IT,2013‐03‐16
6,Eric Liu,19,18531054602,Marketing,2012‐12‐01
7,Chao Zhang,21,13235324334,Administration,2011‐08‐08
8,Kevin Chen,22,13151054603,Sales,2013‐04‐01
9,Shit Wen,20,13351024602,IT,2017‐07‐03
10,Shanshan Du,26,13698424612,Operation,2017‐07‐02