objective c sqlite no select works - objective-c

Question

I can't make a Select on a table in a sqlite database.
I have the following code to copy the .sqlite-file to the user's directory:
// copy the database to the user's directory
- (void)checkAndCreateDB {
// Check if the SQL database has already been saved to the users phone, if not then copy it over
BOOL success;
// Create a FileManager object, we will use this to check the status
// of the database and to copy it over if required
NSFileManager *fileManager = [NSFileManager defaultManager];
// Check if the database has already been created in the users filesystem
success = [fileManager fileExistsAtPath:databasePath];
// If the database already exists then return without doing anything
if(success) return;
// If not then proceed to copy the database from the application to the users filesystem
// Get the path to the database in the application package
NSString *databasePathFromApp = [[NSBundle mainBundle] pathForResource:databaseName ofType:nil];
// Copy the database from the package to the users filesystem
[fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
[fileManager release];
}
And the select here:
sqlite3 *database;
categories = [[NSMutableArray alloc] init];
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
const char *sqlStatement = "select * from category";
sqlite3_stmt *compiledStatement;
NSLog(#"get");
if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
NSLog(#"test");
while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
NSString *cId = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
NSString *cName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
Category *category = [[Category alloc] initWithId:cId name:cName];
[categories addObject:category];
[categories release];
}
}
// Release the compiled statement from memory
sqlite3_finalize(compiledStatement);
}
sqlite3_close(database);
the log shows only: "get". "test" isn't there.
I hope someone can help me.

Answer 1

I believe your database copy code isn't working as you are passing nil to the ofType parameter of [NSBundle pathForResource]. Try passing the correct file extension and add code to detect the success or failure of the copy operation (and make your checkAndCreateDB method return BOOL) and take it from there.
Your database select code looks OK to me, so I'm guess you have an empty database as explained in #Micheal's answer.

Answer 2

sqlite3_open will create a new (empty) database if the one specified doesn't exist. To make sure that this isn't what's happening, try using sqlite3_open_v2 instead and use SQLITE_OPEN_READWRITE as the flags argument. That way you'll get an error if you attempt to open a database that doesn't exist.

Answer 3

There is an example project for using SQLite here you can refer to: https://github.com/AaronBratcher/ABSQLite
It has classes for accessing SQLite in a more traditional database way that I feel makes things easier.