code: private static function isNullable(string $table, string $column): bool
      {
          // IF the nullables cache is not already built, THEN build it!
          if (self::$nullablesCache === null || !array_key_exists($table, self::$nullablesCache))
              self::getNullables($table);
  
          // Return TRUE if the column is included in the nullables cache!
          return array_key_exists($column, self::$nullablesCache[$table]);
      }
docs: Gets the NULL-ability of a column from the specified table schema.
  
  @param string $table The name of the table for which to inspect.
  @param string $column The name of the column for which to check.
  @return bool Returns TRUE if the column is NULL-able, otherwise FALSE.
  @throws DatabaseConnectionException