Sergio Greco is a Full Professor and Chair of the DIMES Department at the University of Calabria (Italy). Before that he was Assistant Professor (1989-1998) and Associate Professor (1998-2000) at the University of Calabria and visiting researcher at the Microelectronics and Computer Corporation of Austin (1990-1991) and at the of University of California at Los Angeles (1996 and 1998). Prof. Greco's research interests include database theory, data integration, inconsistent data, data mining, knowledge representation, logic programming, and computational logic. Cristian Molinaro received his Ph.D. degree in Computer Science Engineering from the University of Calabria, Italy. He was a Visiting Scholar at the Department of Computer Science and Engineering of the State University of New York at Buffalo. He was a Faculty Research Assistant at the University of Maryland Institute for Advanced Computer Studies (2009-2011). Currently, he is an Assistant Professor at the University of Calabria,Italy. His research interests include database theory and logic programming.

• Acknowledgments.- Introduction.- Logic and Relational Databases.- Datalog.- Negation.- Function Symbols.- Aggregates.- Query Optimization.- Applications.- Bibliography.- Authors' Biographies .

Sergio Greco is a Full Professor and Chair of the DIMES Department at the University of Calabria (Italy). Before that he was Assistant Professor (1989-1998) and Associate Professor (1998-2000) at the University of Calabria and visiting researcher at the Microelectronics and Computer Corporation of Austin (1990-1991) and at the of University of California at Los Angeles (1996 and 1998). Prof. Greco's research interests include database theory, data integration, inconsistent data, data mining, knowledge representation, logic programming, and computational logic. Cristian Molinaro received his Ph.D. degree in Computer Science Engineering from the University of Calabria, Italy. He was a Visiting Scholar at the Department of Computer Science and Engineering of the State University of New York at Buffalo. He was a Faculty Research Assistant at the University of Maryland Institute for Advanced Computer Studies (2009-2011). Currently, he is an Assistant Professor at the University of Calabria,Italy. His research interests include database theory and logic programming.

• Acknowledgments.- Introduction.- Logic and Relational Databases.- Datalog.- Negation.- Function Symbols.- Aggregates.- Query Optimization.- Applications.- Bibliography.- Authors' Biographies .

Sergio Greco is a Full Professor and Chair of the DIMES Department at the University of Calabria (Italy). Before that he was Assistant Professor (1989-1998) and Associate Professor (1998-2000) at the University of Calabria and visiting researcher at the Microelectronics and Computer Corporation of Austin (1990-1991) and at the of University of California at Los Angeles (1996 and 1998). Prof. Greco's research interests include database theory, data integration, inconsistent data, data mining, knowledge representation, logic programming, and computational logic. Cristian Molinaro received his Ph.D. degree in Computer Science Engineering from the University of Calabria, Italy. He was a Visiting Scholar at the Department of Computer Science and Engineering of the State University of New York at Buffalo. He was a Faculty Research Assistant at the University of Maryland Institute for Advanced Computer Studies (2009-2011). Currently, he is an Assistant Professor at the University of Calabria,Italy. His research interests include database theory and logic programming.

• Acknowledgments.- Introduction.- Logic and Relational Databases.- Datalog.- Negation.- Function Symbols.- Aggregates.- Query Optimization.- Applications.- Bibliography.- Authors' Biographies .