CPP, How to connect to sqlite3 db from string - c++

Question

In my program I need to connect to sqlite db from string.
I receive the sql db (UTF-8) as string from the user, I'm using the sqlite3_open function that receives file path of the db file so I'm creating a file, write the string to it and using it to connect to the db:
sqlite3*
SQLiteUtils::ConnectToDatabase(std::string const& dbStr)
{
sqlite3* db;
std::ofstream dst("sql.db", std::ios::binary);
dst << dbStr;
int const ret = sqlite3_open("sql.db", &db);
if (SQLITE_OK != ret) {
LOG_ERROR("Can't open database: " + std::string(sqlite3_errmsg(db)));
CloseConnectionToDatabase(db);
return nullptr;
}
return db;
}
Is there a way to connect to string without writing the string to file and connect to the file?

Answer 1

Thanks to #Shawn in the comments I used sqlite3_serialize() and sqlite3_deserialize().
This solution work for me:
const char* IN_MEMORY_DB = ":memory:";
sqlite3* ImportDatabase(const std::string &dbStr)
{
sqlite3 *db;
int ret = sqlite3_open(IN_MEMORY_DB, &db);
if (SQLITE_OK != ret)
{
return nullptr;
}
// give serialized buffer ownership to SQLite
unsigned int flags = SQLITE_DESERIALIZE_FREEONCLOSE|SQLITE_DESERIALIZE_RESIZEABLE;
// allocate the serialized buffer from heap, SQLite requires to dynamic allocation for deserialize to work correctly
unsigned char* data = static_cast<unsigned char*>(sqlite3_malloc(dbStr.size()));
if (nullptr == data)
{
sqlite3_close(db);
return nullptr;
}
for (int i = 0; i < dbStr.size(); ++i)
{
data[i] = static_cast<unsigned char>(dbStr[i]);
}
int err = sqlite3_deserialize(db, "main", data, dbStr.size(), dbStr.size(), flags);
if (err != SQLITE_OK)
{
sqlite3_close(db);
return nullptr;
}
return db;
}
In this solution I allocate the sql memory and copy the string to it without writing the data string to file in the middle.

Answer 2

How to connect to sqlite3 db from string
The default behaviour of sqlite3_open is to open/create the db, and so the only thing you need to do is:
int const ret = sqlite3_open(dbStr.c_str(), &db);
// ^^^^^^^^^^^^^