Trying to Fetching data from sqlite database - iphone

Question

Below is my code, i am trying to fetch data from my.sqlite database but it is not executing my if case. It always enters in else condition. What wrong thing i am doing?
I am not able to execute my if case i.e. if(sqlite3_prepare_v2(database, sqlQuerry, -1, &querryStatement, NULL)==SQLITE_OK)
sqlite3 *database;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *databasePath = [documentsDirectory stringByAppendingPathComponent:#"my.sqlite"];
const char* dbPath=[databasePath UTF8String];
if(sqlite3_open(dbPath, &database)==SQLITE_OK)
{
const char *sqlQuerry="SELECT * FROM Contacts;";
sqlite3_stmt *querryStatement;
if(sqlite3_prepare_v2(database, sqlQuerry, -1, &querryStatement, NULL)==SQLITE_OK)
{
NSLog(#"conversion successful....");
while (sqlite3_step(querryStatement)==SQLITE_ROW)
{
NSString *addressField = [[NSString alloc] initWithUTF8String:
(const char *)
sqlite3_column_text(querryStatement, 0)];
NSString *phoneField = [[NSString alloc] initWithUTF8String:
(const char *) sqlite3_column_text(querryStatement, 1)];
NSLog(#"DB ID :- %#",addressField);
NSLog(#"DB NAME :- %#",phoneField);
}
sqlite3_reset(querryStatement);
}
else {
NSLog(#"error while conversion....");
}
sqlite3_close(database);
}
/////////////////////////////////////////////////////////////////////////////////
I tried using FMDB and did it as bellow:
But my *s and *results object are getting nil value and while statement is not executed
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsPath = [paths objectAtIndex:0];
NSString *path = [docsPath stringByAppendingPathComponent:#"my.sqlite"];
FMDatabase* database = [FMDatabase databaseWithPath:path];
[database open];
FMResultSet *s = [database executeQuery:#"SELECT COUNT(*) FROM Contacts"];
while ([s next])
{
int totalCount = [s intForColumnIndex:0];
NSLog(#"Count : %i", totalCount);
}
FMResultSet *results = [database executeQuery:#"select * from Contacts"];
while([results next])
{
NSString *contact_id = [results stringForColumn:#"contact_id"];
NSString *name = [results stringForColumn:#"name"]; //
NSLog(#"User: %# - %#",name, contact_id);
}
[database close];

Answer 1

Replace your first six lines by the following code:
sqlite3 *database;
NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *databasePath = [documentsDirectory stringByAppendingPathComponent:#"my.sqlite"];
NSLog(#"DATABASE PATH=%#",databasePath);
NSFileManager *fn=[NSFileManager defaultManager];
NSError *error;
BOOL success=[fn fileExistsAtPath:databasePath];
if(!success) {
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"my.sqlite"];
success = [fn copyItemAtPath:defaultDBPath toPath:databasePath error:&error];
}
const char *dbPath=[databasePath UTF8String];
if(sqlite3_open(dbPath, &database)==SQLITE_OK)
{
//. . . . your code...//
}

Answer 2

If you have a problem with any sqlite API then you need to report the error using sqlite3_errmsg() (reference) and this will help you track down your problem.
Change your code to report the error and update your question with the log output:
if (sqlite3_open(dbPath, &database) == SQLITE_OK)
{
...
}
else
{
NSLog("Failed to open database '%#': %s", databasePath, sqlite3_error(database));
}
According to the documentation for sqlite3_open() (here):
.... Otherwise an error code is returned. The sqlite3_errmsg() or
sqlite3_errmsg16() routines can be used to obtain an English language
description of the error following a failure of any of the
sqlite3_open() routines.

Answer 3

I found where I was going wrong. I created & inserted data to my database using Core Data. At the time of fetching I wanted to fire very complex queries, so I had to switch to SQLite. I was doing everything fine but getting error: Table not found.
The actual problem was that CoreData changed every table name of my database with a name prepending a "z", so my table name Contacts changed to ZContacts and column names in similar manner. When I opened my sqlite database in SQLite Manager I found where I was wrong.