Query Processing Techniques in the Team-Oriented Database Query Language

In this paper, we introduce the concept “team” and incorporate the team query into data language SQL. Existing relational query languages use tuple variables of tables to specify required data. Queries that are expressed by these languages are used to get all the data which satisfy the specified conditions. While a team variable represents a subset of a table, a team query is to retrieve all the teams that meet certain constraints. We introduce team qualifications and discuss their implementations, The search space of a team query may be very large. Therefore, instead of using conventional breadth-first search method, we adopt a depth-first search method for query processing. Thus, users can always get results, if one exists. In decision support environments the selection of teams with extreme values like maximum or minimum is frequented needed. In some cases, finding such teams is NP-complete or NP-hard. Genetic algorithms are proposed and computational results are presented. We incorporate genetic algorithms in the query optimization algorithm. The approach makes it possible for a DBMS to respond to team queries in a predicate restricted amount of time.