while(sqlite3_step(statement) == SQLITE_ROW) loops never execute - ipad

Question

hi all
i have some problem in using sqlite in IOS. i have select data from database, and then i want to save that data in a variable. But when i use while(sqlite3_step(statement) == SQLITE_ROW) loop, the code never execute.
here is my code :
-(void)retrieveProjectNameFromDb:(NSString *)segmenId{
NSString *query;
NSString *nameProjectStr;
NSString *dbPath = [[NSBundle mainBundle] pathForResource:#"database" ofType:#"sqlite"];
if (sqlite3_open([dbPath UTF8String], &db) != SQLITE_OK) {
sqlite3_close(db);
NSAssert(0, #"Database failed to open.");
}else {
query = [NSString stringWithFormat:#"SELECT remote_projectname, remote_base_uri FROM REMOTE_SETTING WHERE remote_settingid = '%#' ORDER BY remote_projectname", segmenId];
NSLog(#"query : %#", query);
}
sqlite3_stmt *statement;
if(sqlite3_prepare_v2(db, [query UTF8String], -1, &statement, nil)==SQLITE_OK){
NSLog(#"sqlite row : %d", SQLITE_ROW);
NSLog(#"sqlite 3 : %d", sqlite3_step(statement));
while (sqlite3_step(statement) == SQLITE_ROW) {
char *nameProject = (char *)sqlite3_column_text(statement, 0);
if (nameProject == nil) {
NSLog(#"UNNAMED");
}else {
NSLog(#"else");
nameProjectStr = [NSString stringWithUTF8String:nameProject];
}
projectName.text = nameProjectStr;
nameProject = nil;
}
NSLog(#"project name : %#", projectName.text);
sqlite3_close(db);
}
}
when i nslog the value, sqlite3_step(statement) always show 101 and sqlite_row always show 100. Why it can happen??
can somebody help me, please?
thank you
Regards
-risma-

Answer 1

As you mentioned sqlite3_step(statement) always show 101 which means sqlite3_step has finished executions hence it means your sql query is not returning any rows from database. I would recommend you to first check in database if any record exists in table REMOTE_SETTING for remote_settingid which you are referring.
For your reference I took following constant snippet from sqlite.org
#define SQLITE_DONE 101 /* sqlite_step() has finished executing */

Answer 2

Remove the NSLog entry in which you are having sqlite3_step(). Since you have your NSLog statement executing sqlite3_step(), the record is already stepped through here. Hence, your while loop won't execute as there are no more rows to step through.
I think this will surely help you. :)

Answer 3

From your description of the logging output I would guess that your query is returning an empty row set. However I can see two other problems here:
You discard the result of your first call to sqlite3_step, because you log it then immediately call sqlite3_step again. That means you will miss the first row.
You probably should not be closing the database after a single query. You should finalize the statement after the query, but only close the database when your app shuts down.
Try:
if(sqlite3_prepare_v2(db, [query UTF8String], -1, &statement, nil)==SQLITE_OK){
NSLog(#"sqlite row : %d", SQLITE_ROW);
int stepResult = sqlite3_step(statement);
NSLog(#"sqlite 3 : %d", stepResult);
while (stepResult == SQLITE_ROW) {
char *nameProject = (char *)sqlite3_column_text(statement, 0);
if (nameProject == nil) {
NSLog(#"UNNAMED");
}else {
NSLog(#"else");
nameProjectStr = [NSString stringWithUTF8String:nameProject];
}
projectName.text = nameProjectStr;
nameProject = nil;
stepResult = sqlite3_step(statement);
}
NSLog(#"project name : %#", projectName.text);
sqlite3_finalize(&statement);
}

Answer 4

Try with something like this..
sqlite3 *database1;
NSString *sqlStatement1 = #"";
if(sqlite3_open([databasePath UTF8String], &database1) == SQLITE_OK)
{
sqlStatement1 = [NSString stringWithString:#"SELECT uniqueid from shortlisted"];
sqlite3_stmt *compiledStatement1;
if(sqlite3_prepare_v2(database1, [sqlStatement1 cStringUsingEncoding:NSUTF8StringEncoding], -1, &compiledStatement1, NULL) == SQLITE_OK)
{
while(sqlite3_step(compiledStatement1) == SQLITE_ROW)
{
NSString * str = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
}
}
sqlite3_finalize(compiledStatement1);
sqlite3_close(database1);
}
Also close database instance whenever you open them.. if you are not closing an instance then that can cause issues..
Sorry I am pasting this from my project.. but actually I am in a bit hurry... I'll modify this answer when I reach home...