Team-oriented 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 the required data. These queries get all the data which meets the specified constraints. While a team variable represents a subset of a table, a team query is to retrieve all the teams that meet certain constraints. For example, get all the possible nine player teams for a game from a baseball team database. We discuss team qualifications. The search space of a team query may be 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. We present and discuss team queries in relational database systems, however, the concept seems also to be valuable to resolve this kind of query in other query languages or data models.