Why is SQLite record not found? - objective-c

Question

I am trying to program a username/password log in view controller, there is no errors, no warnings in my app but it always output out "match not found" even when i select a username that already exist in my database..I'd really appreciate it if u could help
this is the code:
[super viewDidLoad];
NSString *docsDir;
NSArray *dirPaths;
// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = dirPaths [0];
_databasePath = [[NSString alloc]initWithString:[docsDir stringByAppendingPathComponent:#"bank.db"]];
NSFileManager *filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath:_databasePath] == NO)
{
const char *dbpath = [_databasePath UTF8String];
if (sqlite3_open(dbpath, &_bankDb) == SQLITE_OK)
{
char *errMsg;
const char *sql_stmt = " CREATE TABLE IF NOT EXISTS USER (USERNAME TEXT PRIMARY KEY, PASSWORD TEXT)";
if (sqlite3_exec(_bankDb, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
{
_status.text= #"failed to create table";
}
sqlite3_close(_bankDb);
} else {
_status.text=#"failed to open/create database";
}
}
- (IBAction)findContact:(id)sender {
const char *dbpath = [_databasePath UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &_bankDb) == SQLITE_OK)
{
NSString *querySQL = [NSString stringWithFormat:#"SELECT USERNAME, PASSWORD FROM USER WHERE USERNAME=\"%#\"", _usernameTextField.text];
const char *query_stmt = [querySQL UTF8String];
if (sqlite3_prepare_v2(_bankDb, query_stmt, -1, &statement, NULL) == SQLITE_OK)
{
if (sqlite3_step(statement) == SQLITE_ROW)
{
NSString *usernameField=[[NSString alloc]initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
_usernameTextField.text=usernameField;
NSString *passwordField = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 1) ];
_passwordTextField.text=passwordField;
_status.text=#"match found";
} else {
_status.text=#"match not found";
}
sqlite3_finalize(statement);
}
sqlite3_close(_bankDb);
}
}

Answer 1

You should do the following things,
look at sqlite3_errmsg values if any queries fail (e.g. sqlite3_prepare_v2 does not return SQLITE_OK or sqlite3_step does not return either SQLITE3_DONE or SQLITE3_ROW);
Do not use stringWithFormat with your queries, but rather use ? placeholders and bind values with sqlite3_bind_text
Thus:
if (sqlite3_open(dbpath, &_bankDb) == SQLITE_OK)
{
const char *query_stmt = "SELECT USERNAME, PASSWORD FROM USER WHERE USERNAME=?";
if (sqlite3_prepare_v2(_bankDb, query_stmt, -1, &statement, NULL) != SQLITE_OK)
NSAssert(0, #"prepare failed: %s", sqlite3_errmsg(_bankDb));
if (sqlite3_bind_text(statement, 1, [_usernameTextField.text UTF8String], -1, NULL) != SQLITE_OK)
NSAssert(0, #"bind failed: %s", sqlite3_errmsg(_bankDb));
int rc = sqlite3_step(statement);
if (rc == SQLITE_ROW)
{
NSString *usernameField=[[NSString alloc]initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
_usernameTextField.text=usernameField;
NSString *passwordField = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 1) ];
_passwordTextField.text=passwordField;
_status.text=#"match found";
} else if (rc == SQLITE_DONE) {
_status.text=#"match not found";
} else {
NSAssert(0, #"step failed: %s", sqlite3_errmsg(_bankDb));
}
sqlite3_finalize(statement);
sqlite3_close(_bankDb);
}
If you're still failing with match not found, you should:
examine the contents of _usernameTextField.text to make sure your IBOutlet is hooked up correctly.
look at the contents of the database and make sure a record with the desired userid is found; you haven't shown us where you add the userid, so it's hard for us to diagnose why the userid in question was not found.
I must confess that the overall logic (just looking for matching records for that userid and populating the password field if you found the userid) looks highly suspect (you shouldn't be storing passwords in plaintext, you certainly shouldn't be returning a password provided simply a userid), but I'm focusing solely on the tactical issue of why you're seeing match not found error message.