Recursion and Stratification in SQL3 and Datalog

Table of Contents

Recursion and Stratification in SQL3 and Datalog

Stratified Negation

Stratified Negation (II)

Problem with Recursive Negation

Strata

Example

Example

Computing Strata

Examples

Stratified Negation

Stratified Model

Example

Example (II)

Is the Stratified Solution "Obvious"?

Is the Stratified Solution "Obvious"? (II)

SQL3 Recursion

Example

Example (II)

Plan for Describing Legal SQL3 recursion

Monotonicity

Monotonicity Example

Monotonicity Example (II)

Generalizing Stratum Graph to SQL

Generalizing Stratum Graph to SQL (II)

Generalizing Stratum Graph to SQL (III)

Example

A Nonmonotonic Example

A Nonmonotonic Example (II)

Another Example: NOT Doesn't Mean Nonmonotone

Another Example: NOT Doesn't Mean Nonmonotone (II)

Email: burt@umbc

Home Page: www.cs.umbc.edu/~burt