如何从iPhone中的SQLite数据库中删除表数据

Question

I am working on a SQLite database. I am inserting data into database that's fine. But I want to delete data from database its not working, I think I am doing wrong some where following is my code please any one help me:

-(IBAction)deleteData {

NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
NSString *databasePath=[documentsDir stringByAppendingPathComponent:@"paddleEight.sqlite"];
NSLog(@"The Database Path is---> %@", databasePath);

sqlite3_stmt *compiledStatement;
sqlite3 *db;
NSString *sqlStatement = @"DELETE  from GalleryTabel;";


if (sqlite3_open([databasePath UTF8String], &db) == SQLITE_OK) {


    if (sqlite3_prepare(db, [sqlStatement UTF8String], -1, &compiledStatement, NULL) == SQLITE_OK) {

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"record" message:@"record Deleted" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];   
        [alert show];
        [alert release];
        alert=nil;
    }
    sqlite3_finalize(compiledStatement);
}
}

Answer 1

Try logging NSLog(@"Error=%s",sqlite3_errmsg(&db) , see if there are any errors. Check if it enters inside the sqlite3_open statement .

And i've never used semicolon to end the delete statement, my knowledge in sqlite is very limited. But i've always used NSString *sqlStatement = @"DELETE from GalleryTabel"; Note the semicolon is removed.

And try using exec instead of prepare,step,finalize method.

For example :

NSString*deleteSQL=[NSString stringWithFormat:@"delete from GalleryTabel"];
const char*deleteStmt=[deleteScoreSQL UTF8String];
 char*errMsg=nil;

        if(sqlite3_exec(db, deleteScoreStmt, NULL, NULL, &errMsg)==SQLITE_OK)
        {
           NSLog(@"Deleted table");
        }

Hope this helps.