从sqlite数据库中删除记录

Question

I am new to ios Development. Can you help me to delete a record from a table. Database and query seems fine. But I dont know why its not deleteing the records. I Can see the nslog "profile deleted" in my console. Thanks in advance.

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    self.str_databasePath = [documentsDirectory stringByAppendingPathComponent:@"MY_database.sqlite"];

    sqlite3 *database = nil;

    if (sqlite3_open([self.str_databasePath UTF8String], &database) == SQLITE_OK)
    {
        NSLog(@"database opened : %@", profileType);
        const char* sqlStatement;
        if([profilerType isEqualToString:@"personal"]){
            sqlStatement = "DELETE FROM TABLE1 where profile_type = 'OWN_PERSONAL'";
        }else if([profilerType isEqualToString:@"corporate"]){
            sqlStatement = "DELETE FROM TABLE2 where profile_type = 'BANK_PROFILE'";  
        }
        sqlite3_stmt *statement;

        if(sqlite3_prepare_v2(database, sqlStatement, -1, &statement, NULL) == SQLITE_OK)
        {
            NSLog(@"profile deleted ");
            return YES;
        }else{

            NSAssert1(0,@"Error: Failed to prepare statement with message %s '.", sqlite3_errmsg(database));
        }


        // Finalize and close database.
        sqlite3_finalize(statement);
        sqlite3_close(database);
    }
     return NO;

Answer 1

As HeikoG said, it's much easier to use Core Data. Core Data is basically an SQLite db, but it's much easier to use. Have a look at this tutorial: http://www.raywenderlich.com/934/core-data-tutorial-getting-started

You will probably save time if you use that instead of using SQL directly, even if you have to re-write your current code.

Answer 2

It's not deleting records because you're only preparing the query, never executing it.

To execute a prepared query, you must call sqlite3_step

Alternatively, you can use sqlite3_exec which is a convenience function that performs prepare, step and finalize.