sqlite3中表名可以使用参数吗?
我对 sqlite3 参数 有一些奇怪的感觉,我想向您公开。
这是我的查询和失败消息:
#query
'SELECT id FROM ? WHERE key = ? AND (userid = '0' OR userid = ?) ORDER BY userid DESC LIMIT 1;'
#error message, fails when calling sqlite3_prepare()
error: 'near "?": syntax error'
在我的代码中,它看起来像:
// Query is a helper class, at creation it does an sqlite3_preprare()
Query q("SELECT id FROM ? WHERE key = ? AND (userid = 0 OR userid = ?) ORDER BY userid DESC LIMIT 1;");
// bind arguments
q.bindString(1, _db_name.c_str() ); // class member, the table name
q.bindString(2, key.c_str()); // function argument (std::string)
q.bindInt (3, currentID); // function argument (int)
q.execute();
我有一种感觉,我无法使用 sqlite parameters 作为表名,但我无法在Sqlite3 C API。
你知道我的查询有什么问题吗?
在准备查询之前,我是否必须预处理 SQL 语句以包含表名?
I'm having some strange feeling abour sqlite3 parameters that I would like to expose to you.
This is my query and the fail message :
#query
'SELECT id FROM ? WHERE key = ? AND (userid = '0' OR userid = ?) ORDER BY userid DESC LIMIT 1;'
#error message, fails when calling sqlite3_prepare()
error: 'near "?": syntax error'
In my code it looks like:
// Query is a helper class, at creation it does an sqlite3_preprare()
Query q("SELECT id FROM ? WHERE key = ? AND (userid = 0 OR userid = ?) ORDER BY userid DESC LIMIT 1;");
// bind arguments
q.bindString(1, _db_name.c_str() ); // class member, the table name
q.bindString(2, key.c_str()); // function argument (std::string)
q.bindInt (3, currentID); // function argument (int)
q.execute();
I have the feeling that I can't use sqlite parameters for the table name, but I can't find the confirmation in the Sqlite3 C API.
Do you know what's wrong with my query?
Do I have to pre-process my SQL statement to include the table name before preparing the query?
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哦,好吧,应该更彻底地研究一下。
答案:
- SQLite 参数 - 不允许表名作为参数
- sqlite 中的变量表名称
它们适用于 Python,但我想这同样适用对于C++。
tl;dr:
您不能将表名称作为参数传递。
如果有人在 SQLite 文档中提供了我对此进行确认的链接,我将很乐意接受答案。
Ooookay, should have looked more thoroughly on SO.
Answers:
- SQLite Parameters - Not allowing tablename as parameter
- Variable table name in sqlite
They are meant for Python, but I guess the same applies for C++.
tl;dr:
You can't pass the table name as a parameter.
If anyone have a link in the SQLite documentation where I have the confirmation of this, I'll gladly accept the answer.
我知道这已经非常旧了,但是由于您的查询只是一个字符串,您始终可以在 C++ 中附加表名称:
或在 Objective-C 中:
I know this is super old already but since your query is just a string you can always append the table name like this in C++:
or in objective-C: