This paper presents a comprehensive framework for representing and querying spatio-temporal data, particularly moving objects. The authors propose a set of abstract data types and operations to handle time-dependent geometries, including moving points and regions. The framework aims to provide a precise and conceptually clean foundation for implementing a spatio-temporal DBMS extension. Key design principles include orthogonality, genericity, and consistency. The paper defines the types and operations formally, discusses their implementation in SQL-like languages, and explores their expressive power through examples. The framework supports both discrete and continuous moving objects, addressing the challenges of representing and querying such data in databases.This paper presents a comprehensive framework for representing and querying spatio-temporal data, particularly moving objects. The authors propose a set of abstract data types and operations to handle time-dependent geometries, including moving points and regions. The framework aims to provide a precise and conceptually clean foundation for implementing a spatio-temporal DBMS extension. Key design principles include orthogonality, genericity, and consistency. The paper defines the types and operations formally, discusses their implementation in SQL-like languages, and explores their expressive power through examples. The framework supports both discrete and continuous moving objects, addressing the challenges of representing and querying such data in databases.