LectureNotesOnPython.rst: 在inheritance那节加了数据库sqlite添加与搜索的例子

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diff --git a/LectureNotesOnPython.rst b/LectureNotesOnPython.rst
index 0b0c4f2..647835a 100644
--- a/LectureNotesOnPython.rst
+++ b/LectureNotesOnPython.rst
@@ -2039,6 +2039,68 @@ IS-A 。 一手牌是一副牌。
          
 
 
+用于数据库操作。以 SQLite 为例子。
+
+
+.. code:: python
+
+         # Reference: Dusty Phillips.  Python 3 Objected-oriented Programming Second Edition. Pages 326-328.
+         # Copyright (C) 2019 Hui Lan
+         
+         import sqlite3
+         
+         class Sqlite3Template:
+             def __init__(self, db_fname):
+                 self.db_fname = db_fname
+                 
+             def connect(self, db_fname):
+                 self.conn = sqlite3.connect(self.db_fname)
+             
+             def instructions(self, query_statement):
+                 raise NotImplementedError()
+             
+             def operate(self):
+                 self.results = self.conn.execute(self.query) # self.query is to be given in the child classes
+                 self.conn.commit()
+                 
+             def format_results(self):
+                 raise NotImplementedError()  
+             
+             def do(self):
+                 self.connect(self.db_fname)
+                 self.instructions(self.query)
+                 self.operate()
+                 
+                 
+         class InsertQuery(Sqlite3Template):
+             def instructions(self, query):
+                 self.query = query
+                 
+         
+         class RiskQuery(Sqlite3Template):
+             def instructions(self, query):
+                 self.query = query
+         
+             def format_results(self):
+                 output = []
+                 for row in self.results.fetchall():
+                     output.append(', '.join([str(i) for i in row]))
+                 return '\n'.join(output)    
+         
+         
+         if __name__ == '__main__':
+             
+             #iq = InsertQuery('RiskDB.db')
+             #iq.instructions("INSERT INTO inspection Values ('FoodSupplies', 'RI2019051301', '2019-05-13', '{}')")
+             #iq.do()
+             #iq.instructions("INSERT INTO inspection Values ('CarSupplies', 'RI2019051302', '2019-05-13', '{[{\"risk_name\":\"elevator\"}]}')")
+             #iq.do()
+             
+             rq = RiskQuery('RiskDB.db')
+             rq.instructions("SELECT * FROM inspection WHERE inspection_serial_number LIKE 'RI20190513%'")
+             rq.do()
+             print(rq.format_results())
+         
 
 web 应用程序
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