DBSnap++: creating data-driven programs by snapping blocks

A key development in Computer Science Education has been the introduction of block-based programming environments where programs are created by connecting blocks and the focus is on the program's logic instead of its syntax. Most of these environments support conventional (imperative) programming instructions. More recently, some systems have been proposed to enable the specification of database queries. While these two types of environments have been independently studied, there is significantly less work on the development and study of integrated environments that allow the creation of complete data-driven programs (real-world like programs that integrate conventional instructions and database queries). This paper introduces DBSnap++, a web-based environment that enables the specification of dynamic data-driven programs. DBSnap++ supports the specification of intuitive database query trees, a new type of list that dynamically gets its content executing a database query, and programs that generate different results when the underlying data changes. This paper presents DBSnap++'s design and implementation details, an array of programs to demonstrate how it can be effectively used as a learning tool, and a thorough comparison with other environments. DBSnap++ is publicly available and aims to enable learners to fully understand and utilize the capabilities of data-driven programs.