Add database demo with sqlite3 based on OOP

Author: adipandas

DatabaseOOP/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>DatabaseOOP</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.python.pydev.PyDevBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.python.pydev.pythonNature</nature>
+	</natures>
+</projectDescription>

DatabaseOOP/.pydevproject

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+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<?eclipse-pydev version="1.0"?><pydev_project>
+<pydev_pathproperty name="org.python.pydev.PROJECT_SOURCE_PATH">
+<path>/${PROJECT_DIR_NAME}/src</path>
+</pydev_pathproperty>
+<pydev_property name="org.python.pydev.PYTHON_PROJECT_VERSION">python 3.6</pydev_property>
+<pydev_property name="org.python.pydev.PYTHON_PROJECT_INTERPRETER">Default</pydev_property>
+</pydev_project>

DatabaseOOP/src/databaseoop.py

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+'''
+Created on Aug 9, 2017
+
+@author: sayalik157
+'''
+
+import sqlite3      # python lib for sqlite3 database handling 
+
+class database:
+    def __init__(self, **kwargs):
+        # note: because of decorators _filename and _table are set from filename and file respectively
+        self.filename = kwargs.get('filename')
+        self.table = kwargs.get('table', 'test')     # default tablename set as 'test'
+        
+    def sql_do(self, sql, *params): 
+        # arbitrary number of *params are given incase more parameters are needed for 'sql' command
+        self._db.execute(sql, params)   # execute sql command on database
+        self._db.commit()
+
+    def insert(self, row):      # inserting a row in database
+        self._db.execute('insert into {} (t1, i1) values (?, ?)'.format(self._table), (row['t1'], row['i1']))
+        self._db.commit()
+        
+    def retrieve(self, key):                # to retrieve a row from database
+        cursor = self._db.execute('select * from {} where t1 = ?'.format(self._table), (key,))
+        return dict(cursor.fetchone())      # fetch only one in dictionary form
+    
+    def update(self, row):          # to update a row in database
+        self._db.execute('update {} set i1 = ? where t1=?'.format(self._table), (row['i1'], row['t1']))
+        self._db.commit()
+        
+    def delete(self, key):
+        self._db.execute('delete from {} where t1 = ?'.format(self._table), (key,))
+        
+    def display_rows(self):
+        cursor = self._db.execute('select * from {} order by t1'.format(self._table))
+        for row in cursor:
+            print('{}:{}'.format(row['t1'], row['i1']))
+
+    def __iter__(self):
+        cursor = self._db.execute('select * from {} order by t1'.format(self._table))
+        for row in cursor:
+            yield dict(row)
+        
+    @ property          # filename getter decorator
+    def filename(self): return self._filename
+    
+    @filename.setter    # filename setter decorator
+    def filename(self, filename):
+        self._filename = filename
+        self._db = sqlite3.connect(self._filename)
+        self._db.row_factory = sqlite3.Row
+    
+    @filename.deleter   # filename deleter decorator
+    def filname(self): self.close()     # close the database
+    
+    @property       #decorator to get tablename
+    def table(self): return self._table
+    @table.setter   # decorator to set tablename
+    def table(self, t): self._table = t
+    @table.deleter  # decorator to delete tablename
+    def table(self): self._table = 'test'
+
+    def close(self):
+            self._db.close()    # close the database
+            del self._filename
+            
+def main():
+    db = database(filename = 'test.db', table = 'test')
+
+    print('Create table test')
+    db.sql_do('drop table if exists test')
+    db.sql_do('create table test ( t1 text, i1 int )')
+
+    print('Create rows')
+    db.insert(dict(t1 = 'one', i1 = 1))
+    db.insert(dict(t1 = 'two', i1 = 2))
+    db.insert(dict(t1 = 'three', i1 = 3))
+    db.insert(dict(t1 = 'four', i1 = 4))
+    for row in db: print(row)
+
+    print('Retrieve rows')
+    print(db.retrieve('one'), db.retrieve('two'))
+
+    print('Update rows')
+    db.update(dict(t1 = 'one', i1 = 101))
+    db.update(dict(t1 = 'three', i1 = 103))
+    for row in db: print(row)
+
+    print('Delete rows')
+    db.delete('one')
+    db.delete('three')
+    for row in db: print(row)
+
+    print('Done!!')
+if __name__ == '__main__':main()