A logical language for data and knowledge bases

This is a comprehensive account of the syntax and semantics of a new programming language called [script capitals]LDL. In it are provided descriptions, both at the informal and formal level, of every [script capitals]LDL construct. The informal descriptions to not presuppose a high technical inclination but nevertheless are precise. For the avid and mathematically inclined, advanced sections are provided detailing model-theoretic and constructive semantics of the language. These advanced sections themselves and by the nature of the language also serve as introductions to current research topics in the theory of Data and Knowledge Bases. The authors have striven for simplicity and brevity, but not at the expense of accuracy