During the current Covid-19 pandemic, it is necessary to have facilities track community activities make easier cope with pandemic situation which still a threat community. Contact tracing application (Contact Tracing) one solution that can be used in this regard. By utilizing Tracing, people's recorded when traveling meet other people so they generate history someone if of them infected Covid-...

Standard SQL is incapable of handling recursive database queries and nested relations. A proposed solution to allow recursion in SQL was given in SQL KC93], while a solution to allow nested relations in SQL was given in SQL=NF RKB87]. However, these two problems with SQL were handled separately, and an extended SQL that handles both recursive queries and nested relations is still lacking. To ov...

NoSQL databases support semi-structured data, typically modeled as JSON. They also provide limited (but expanding) query languages. Their idiomatic, non-SQL language constructs, the many variations, and the lack of formal semantics inhibit deep understanding of the query languages, and also impede progress towards clean, powerful, declarative query languages. This paper specifies the syntax and...

SQL-on-Hadoop, NewSQL and NoSQL databases provide semi-structured data models (typically JSON based) and respective query languages. Lack of formal syntax and semantics, idiomatic (nonSQL) language constructs and large variations in syntax, semantics and actual capabilities pose problems even to database experts: It is hard to understand, compare and use these languages. It is especially tediou...

We consider IES(SQL), the incremental evaluation system over an SQL-like language with grouping, arithmetics, and aggregation. We show that every second order query is in IES(SQL) and that there are PSPACE-complete queries in IES(SQL). We further show that every PSPACE query is in IES(SQL) augmented with a deterministic transitive closure operator. Lastly, we consider ordered databases and prov...

If you want to get SQL, Second Edition pdf eBook copy write by good author Fehily, Chris, SQL Injection Attacks and Defense, Second Edition / BackTrack. Confirming and Recovering from SQL Injection Attacks Introduction an SQL injection flaw (ftc.gov/os/caselist/0523148/0523148complaint.pdf), a hacker. One of the most easiest and hazardous security attacks confronted by these systems is SQL inje...