FMDB

//create
NSFileManager * fileManager = [NSFileManager defaultManager];
			if ([fileManager fileExistsAtPath:self.dbPath] == NO) {
				// create it
				FMDatabase * db = [FMDatabase databaseWithPath:self.dbPath];
				if ([db open]) {
					NSString * sql = @"CREATE TABLE 'User' ('id' INTEGER PRIMARY KEY AUTOINCREMENT  NOT NULL , 'name' VARCHAR(30), 'password' VARCHAR(30))";
					BOOL res = [db executeUpdate:sql];
					if (!res) {
						debugLog(@"error when creating db table");
					} else {
						debugLog(@"succ to creating db table");
					}
					[db close];
				} else {
					debugLog(@"error when open db");
				}
			}
			
//insert
			static int idx = 1;
			FMDatabase * db = [FMDatabase databaseWithPath:self.dbPath];
			if ([db open]) {
				NSString * sql = @"insert into user (name, password) values(?, ?) ";
				NSString * name = [NSString stringWithFormat:@"tangqiao%d", idx++];
				BOOL res = [db executeUpdate:sql, name, @"boy"];
				if (!res) {
					debugLog(@"error to insert data");
				} else {
					debugLog(@"succ to insert data");
				}
				[db close];
			}


//query
debugMethod();
			FMDatabase * db = [FMDatabase databaseWithPath:self.dbPath];
			if ([db open]) {
				NSString * sql = @"select * from user";
				FMResultSet * rs = [db executeQuery:sql];
				while ([rs next]) {
					int userId = [rs intForColumn:@"id"];
					NSString * name = [rs stringForColumn:@"name"];
					NSString * pass = [rs stringForColumn:@"password"];
					debugLog(@"user id = %d, name = %@, pass = %@", userId, name, pass);
				}
				[db close];
			}

//clear
FMDatabase * db = [FMDatabase databaseWithPath:self.dbPath];
			if ([db open]) {
				NSString * sql = @"delete from user";
				BOOL res = [db executeUpdate:sql];
				if (!res) {
					debugLog(@"error to delete db data");
				} else {
					debugLog(@"succ to deleta db data");
				}
				[db close];
			}