sqlite3.OperationalError: unrecognized token: ":"

最新推荐文章于 2024-12-28 10:40:38 发布

原创最新推荐文章于 2024-12-28 10:40:38 发布 · 837 阅读

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本文详细介绍了在Python使用SQLite3模块时遇到的SQL执行错误，从原始代码中的问号风格参数化转换为命名风格参数化，成功解决了未识别符号的错误，最终代码实现正确执行SQL查询并返回预期结果。

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看《集体智慧编程》第四章中定义getentryid()报了 sqlite3.OperationalError: unrecognized token: ":" 错误。

 def getentryid(self,table,field,value,createnew=True):
    cur=self.con.execute(
    "select rowid from %s where %s=%s" % (table,field,value))
    res=cur.fetchone()
    if res==None:
      cur=self.con.execute(
      "insert into %s (%s) values (%s)" % (table,field,value))
      return cur.lastrowid
    else:
      return res[0]

然后想起来，好像把

cur=self.con.execute("select rowid from %s where %s=%s" % (table,field,value))

中第三个%s的引号去掉了，结果加上引号好像之前报了个什么引号找不到还是无法识别的错误。

然后查了好多，最后看文档

execute(sql[, parameters])

Executes an SQL statement. The SQL statement may be parameterized (i. e. placeholders instead of SQL literals). The sqlite3 module supports two kinds of placeholders: question marks (qmark style) and named placeholders (named style).

Here’s an example of both styles:

import sqlite3

con = sqlite3.connect(":memory:")
cur = con.cursor()
cur.execute("create table people (name_last, age)")

who = "Yeltsin"
age = 72

# This is the qmark style:
cur.execute("insert into people values (?, ?)", (who, age))

# And this is the named style:
cur.execute("select * from people where name_last=:who and age=:age", {"who": who, "age": age})

print(cur.fetchone())

execute() will only execute a single SQL statement. If you try to execute more than one statement with it, it will raise a Warning. Use executescript() if you want to execute multiple SQL statements with one call.

按照named style 把原来的代码改成了(insert改qmark style 还是报错不知道为什么 = =)

    def getentryid(self, table, field, value, createnew = True):
        cur = self.con.execute("select rowid from %s where %s = :value " % (table, field), {"value": value})
        res = cur.fetchone()
        if res is None:
            cur = self.con.execute("insert into %s (%s) values (:value)" % (table, field), {"value": value})
            return cur.lastrowid
        else:
            return res[0]

哈哈，没报错~\(≧▽≦)/~啦啦啦