Sqlite3_step() keeps returning SQLITE_MISUSE on this query. Any pointers?

Question

I am trying to open a sqlite db in the viewDidLoad routine and trying to send a sql query through to the db, but the sqlite_step() fails every time. I am not sure what's wrong here. I am just trying this as a hello world attempt at sqlite3.

#import "RootViewController.h"
#import "sqlite3.h"

static sqlite3_stmt *statement = nil;

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSString *dbname = @"name.sqlite";
    sqlite3 *database;
    int success;

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:dbname];
    // Open the database. The database was prepared outside the application.
    success = sqlite3_open([path UTF8String], &database);
    if (success == SQLITE_OK) {
        NSLog(@"database opening successful : %d", success);
    } else {
        // Even though the open failed, call close to properly clean up resources.
        sqlite3_close(database);
        NSLog(@"database opening failed : %d", success);
        // Additional error handling, as appropriate...
    }
    if (statement == nil) {
        const char *sql = "insert into name(nid, name) values(6, 'testname');";
        success = sqlite3_prepare_v2(database, sql, -1, &statement, NULL);
        NSLog(@"query prepare status: %d", success);
        if (success != SQLITE_OK) {
        }
    }

    success = sqlite3_step(statement); //things fail here, as all calls above return ok
    NSLog(@"query step status: %d", success);
    if (success != SQLITE_DONE) {
    }
    sqlite3_reset(statement);
    sqlite3_close(database);
}
...

It would be great if anyone could point me out where I might be wrong. Thanks for your time already.

Answer 1

Have you verified that the statement compiles OK? You have the success = sqlite3_prepare_v2(...); line, but never do anything if success is not SQLITE_OK. Have you verified that it is SQLITE_OK?

On the other hand, if you were to use a wrapper like FMDB, you could replace all of your code above with:

- (void)viewDidLoad {
    [super viewDidLoad];
    NSString *dbname = @"name.sqlite";
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:dbname];
    FMDatabase * database = [FMDatabase databaseWithPath:path];

    [database executeUpdate:@"insert into name(nid, name) values(?, ?)", [NSNumber numberWithInt:6], @"testname"];
    [database close];
}

This, IMO, is much easier to debug.

Answer 2

I did this but it still doesn't work, as in nothing shows up in the Console.

#import "RootViewController.h"
#import "FMDatabase.h"

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSString *dbname = @"name.sqlite";
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:dbname];
    FMDatabase * database = [FMDatabase databaseWithPath:path];
    FMResultSet *rs = [database executeQuery:@"select * from name;"];
    while ([rs next]) {
        NSLog(@"%d %@",
              [rs intForColumn:@"nid"],
              [rs stringForColumn:@"name"]);
    }
    [database close];
}
...

And sorry but am unable to use the code block, so using a pre again.

Edit: When I turn logging on in FMDB, like this:

    FMDatabase * database = [FMDatabase databaseWithPath:path];

    [database setLogsErrors:YES];

    if (![database open]) { 
        NSLog(@"Could not open db."); 
    } else { 
        NSLog(@"DB Open...."); 
    }
    FMResultSet *rs = [database executeQuery:@"select * from 'name';"];
    while ([rs next]) {
        // just print out what we've got in a number of formats.
        NSLog(@"%d %@",
              [rs intForColumn:@"nid"],
              [rs stringForColumn:@"name"]);
    }
    [database close];

..., I get this in the Console:

[Session started at 2010-09-07 15:38:16 +0530.]
2010-09-07 15:38:19.178 MyDBTry[13670:207] DB Open....
2010-09-07 15:38:19.181 MyDBTry[13670:207] DB Error: 1 "no such table: name"
2010-09-07 15:38:19.182 MyDBTry[13670:207] DB Query: select * from name;