【python】数据库操作

SQLite3 可使用 sqlite3 模块与 Python 进行集成。我们可视化工具使用SQLLite  Expert。

# -*- coding:UTF-8 -*-
#参考资料:https://wizardforcel.gitbooks.io/w3school-db/content/sql/110.html
#参考资料:http://blog.csdn.net/zmq570235977/article/details/50396313 (SQLLite可视化工具：SQLiteExpert)
import sqlite3

dbName = "test.db"

conn = sqlite3.connect(dbName)

conn.execute('''CREATE TABLE IF NOT EXISTS COMPANY
(ID INT PRIMARY KEY NOT NULL,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL)''')
print "Table created successfully"

conn.close()

conn = sqlite3.connect(dbName)
print "Opened database successfully";

conn.execute("INSERT OR REPLACE INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (1, 'Paul', 32, 'California', 20000.00 )");

conn.execute("INSERT OR REPLACE INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (2, 'Allen', 25, 'Texas', 15000.00 )");

conn.execute("INSERT OR REPLACE INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (3, 'Teddy', 23, 'Norway', 20000.00 )");

conn.execute("INSERT OR REPLACE INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 )");

conn.commit()
print "Records created successfully";
conn.close()

conn = sqlite3.connect(dbName)
print "Opened database successfully";

cursor = conn.execute("SELECT id, name, address, salary from COMPANY")
for row in cursor:
print "ID = ", row[0]
print "NAME = ", row[1]
print "ADDRESS = ", row[2]
print "SALARY = ", row[3], "\n"

print "Operation done successfully";
conn.close()

我们需要特别注意的是当一个表已经存在和一个表中记录已经存在的时候。我以前是用SQL Server，他是直接可以使用if not exists(select 1 from table_A where ID = 1)  insert XXXX
但是SQLLite不行，他用INSERT OR REPLACE INTO