[Programmer technical skills] Learning a scripting language python (3) dealing with databases, Scripting Language python

[Programmer technical skills] Learning a scripting language python (3) dealing with databases, Scripting Language python

Next, the previous article describes how to use python to perform basic CRUD operations on the database. Here, we will describe sqlite3 as an example. Sqlite3 is a very lightweight database. It is very simple to install and use. I will not discuss it here.

In python, The sqlite3 module is provided for our use. The usage of this module is similar to that of the jdbc driver in JAVA, we can easily perform various operations with sqlite3.

 

Okay. Let's get started.

The python database module has a unified interface standard, and all operations have a unified mode, which is roughly divided into the following steps (assuming the sqlite3 module is used ):

 

The specific CRUD implementation code is as follows:

Import osimport sqlite3 # obtain a database connection based on the input path. if the path is invalid, create a temporary memory database def get_conn (path): conn = sqlite3.connect (path) if OS. path. exists (path) and OS. path. isfile (path): print ('database path is % s' % format (path) return conn else: conn = None return sqlite3.connect (': memory ')

 

# Retrieve the cursor def get_cursor (conn): if conn is not None: return conn. cursor () else: return get_conn (''). cursor ()

 

# Create table data def create_table (conn, SQL): if SQL is not None and SQL! = '': Cursor = get_cursor (conn) cursor.exe cute (SQL) conn. commit () close_all (conn, cursor) # Close the database connection def close_all (conn, cursor): try: if cursor is not None: cursor. close () finally: if conn is not None: conn. close ()

 

# The return value is required for the CURD operation. The query must return the value def crud (conn, SQL, data): cursor = get_cursor (conn) n = cursor.exe cute (SQL, data) print ("n", n. rowcount) fetchall = cursor. fetchall () conn. commit () close_all (conn, cursor) return fetchall

 

 

# The CRUD operation does not require the return value. The query must return the def crud (conn, SQL, data): cursor = get_cursor (conn) n = cursor.exe cute (SQL, data) conn. commit () close_all (conn, cursor)

 

 

A simple example:

Conn = get_conn ('d:/temp/sqlite3/test. db ') fetchall = crud (conn, 'select * from student', '') # assume that the returned data has three fields for row in fetchall: print ('name: % s, age: % d, address: % s' % (row [0], row [1], row [2])

 

 

 

The above code is the simplest operation on the python database.

If you have any questions or file errors, you can leave a message for discussion!