从SQLite中的准备语句获取原始SQL查询 [英] Get original SQL query from prepared statement in SQLite

问题描述

我使用SQLite（3.6.4）从C + +应用程序（使用标准C api）。我的问题是：一旦使用 sqlite3_prepare_v2（），并使用 sqlite3_bind_xyz（） - 有没有办法得到一个包含原始SQL查询的字符串？

I'm using SQLite (3.6.4) from a C++ application (using the standard C api). My question is: once a query has been prepared, using sqlite3_prepare_v2(), and bound with parameters using sqlite3_bind_xyz() - is there any way to get a string containing the original SQL query?

原因是当出现错误时，我打印查询（用于调试 - 这是一个内部开发人员测试应用程序。

The reason is when something goes wrong, I'd like to print the query (for debugging - this is an in-house developer only test app).

示例：

sqlite3_prepare_v2(db, "SELECT * FROM xyz WHERE something = ? AND somethingelse = ?", -1, &myQuery, NULL);
sqlite3_bind_text(myQuery, 1, mySomething);
sqlite3_bind_text(myQuery, 2, mySomethingElse);
// ....

// somewhere else, in another function perhaps
if (sqlite3_step(myQuery) != SQLITE_OK)
{
     // Here i'd like to print the actual query that failed - but I 
     // only have the myQuery variable
     exit(-1);
}

如果它也可以打印出绑定的实际参数， ：

Bonus points if it could also print out the actual parameters that was bound. :)

推荐答案

根据sqlite3.c（amalgamation）中的注释， sqlite3_sql（myQuery）将返回原始的SQL文本。

As per the comments in sqlite3.c (amalgamation), sqlite3_sql(myQuery) will return the original SQL text.

看到任何函数找到在特定索引绑定的值，但我们可以轻松地添加一个标准的SQLite函数集。它可能看起来像这样：

I don't see any function for finding the value bound at a particular index, but we can easily add one to the standard set of SQLite functions. It may look something like this:

const char* sqlite3_bound_value(sqlite3_stmt* pStmt, int index)
{
  Vdbe *p = (Vdbe *)pStmt;

  // check if &p->aVar[index - 1] points to a valid location.
  return (char*)sqlite3ValueText(&p->aVar[index - 1], SQLITE_UTF8);
}

好吧，上面的代码只显示了一个可能的方法sqlite3_bound_value 。我没有测试它，它可能是错误的，但它给出了一些提示如何/从哪里开始。

Well, the above code shows only a possible way sqlite3_bound_value() could be implemented. I haven't tested it, it might be wrong, but it gives certain hints on how/where to start.

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