Question

使用Python和Sqlite3 如何从sqlite中获取值，将其存储在变量中，然后向其中添加一个字符串并更新它？

import sqlite3

connection = sqlite3.connect("intel.db")
database   = connection.cursor()

u                   = 'Zero'
all     = database.execute("SELECT * FROM logs")
newtext = ' message.content '

for w in all:
    if u in w[1]:
        print("exist")
        olddata = database.execute("SELECT logtext FROM logs where loguser=? ", (u))

        ## use olddata + newtext then add to updated 

        updated = database.execute("UPDATE logs SET logtext = ? WHERE loguser = ?", (olddata + newtext, u,))
        print("User textlog updated")
    break

Answer 1

是的，你可以，但你需要知道正确的语法，下面我创建了一个新的数据库，并插入两个记录数据，然后从db获取值并更新它：

import sqlite3
conn = sqlite3.connect('intel.db')
database = conn.cursor()
database.execute('''CREATE TABLE logs
             (date text, logtext text, loguser text, qty real, price real)''')

# Insert a row of data
database.execute("INSERT INTO logs VALUES ('2006-01-05','HI','Zero',100,35.14)")
database.execute("INSERT INTO logs VALUES ('2006-01-03','HELLO','David',100,35.14)")

# Save (commit) the changes
conn.commit()

u = 'Zero'
all_data = database.execute("SELECT * FROM logs")
newtext = ' message.content '
for w in all_data:
    if u in w:
        print("exist")
        olddata = database.execute("SELECT logtext FROM logs where loguser=? ", (u,)).fetchone()[0]
        print "Old Data:"
        print olddata
        database.execute("UPDATE logs SET logtext = ? WHERE loguser = ?", (olddata + newtext, u,))
        conn.commit()
        newdata = database.execute("SELECT * FROM logs where loguser=? ", (u,)).fetchone()
        print "New Data:"
        print newdata
conn.close()

输出将是：

exist
Old Data:
HI
New Data:
(u'2006-01-05', u'HI message.content ', u'Zero', 100.0, 35.14)

如您所见，HI已使用新数据HI message.content进行了更新。

我怎样才能获得sqlite的值然后更新它

1 个答案: