CODEWITHSUNDEEP
c++sqliteprepared-statementsql-delete
TVA van Hesteren
TVA van Hesteren

Reputation: 1221

C++ SQLite3 prepared delete statement not working

I have a C++ application which loops through a SQLite3 database. Each row contains an ID which is checked against a vector. If the ID in the DB is not present in the vector, it should be deleted with a prepared statement. I use the following code, however the ID's won't get deleted. I Neither can get an error message from the sqlite3_step(stmt2) function.

//SETTINGS["Reference"] CONTAINS THE REFERENCE FOR THE ID's (IT's 1 FOR UNDERNEATH EXAMPLE)


vector<int> IDs; //THIS VECTOR CONTAINS THE ID's IN MY APPLICATION
rc = sqlite3_prepare_v2(db, "SELECT ID FROM Files WHERE Reference=?", -1, &stmt, 0);
sqlite3_bind_text(stmt, 1, Settings["Reference"].c_str(), Settings["Reference"].length(), 0);
CheckDBError(rc);
rc = sqlite3_step(stmt);
sqlite3_stmt* stmt2;
int rc2 = sqlite3_prepare_v2(db, "DELETE FROM Files WHERE ID=? AND Reference=?", -1, &stmt2, 0);
CheckDBError(rc2);
while(rc == SQLITE_ROW) {
    string IDToCheck = NumberToString(sqlite3_column_int64(stmt, 0));
    if (std::find(IDs.begin(), IDs.end(), IDToCheck) == IDs.end()) { //VERIFY AGAINST VECTOR WORKS AS EXPECTED

        //I GET HERE WITH ALL MY ID's I HAVE CHECKED THAT ALREADY :)

        sqlite3_bind_text(stmt2, 1, IDToCheck.c_str(), IDToCheck.length(), 0);
        sqlite3_bind_text(stmt2, 2, Settings["Reference"].c_str(), Settings["Reference"].length(), 0);
        rc2 = sqlite3_step(stmt2);

        //CAN'T GET ANY ERROR MESSAGE (SO QUERY IS FINE, WHICH SEEMS LIKE IT?)

        }
    rc = sqlite3_step(stmt);
    }
sqlite3_finalize(stmt);
sqlite3_finalize(stmt2);

Upvotes: 0

Views: 1430

Answers (1)

themiurge
themiurge

Reputation: 1669

You must not call the finalize function before the while block, because that way you finalize your statement before using it. As per SQLite documentation (emphasis mine):

It is a grievous error for the application to try to use a prepared statement after it has been finalized. Any use of a prepared statement after it has been finalized can result in undefined and undesirable behavior such as segfaults and heap corruption.

Upvotes: 2

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