Complex Query

Introduction

A user wants to perform a complex query on one or more datasets. A complex query is currently defined by astrogrid as ?a query that can?t be done simply in SQL.? A complex query can combine data from one or more catalogues with one or more expressions. Expressions can be inequalities, astrogrid library expressions, web services, or user code.

Flow of Events

A user accesses the complex query form through a web browser or command line. Next, the user indicates which catalogues or datasets should be queried. Then, the user enters each expression used to make up the query. These expressions may be inequalities, library functions, web services, or user code. The user also indicates workflow for the sequence of expressions (at the very least, the order in which they should be executed). Finally, the complex query is sent to the Estimator as in NegotiateAccessToJob. If the user does not have permission to perform one or more of the query expressions, then the expression(s) must be edited or removed before the complex query will be executed.

Sequence Diagram

-- ElizabethAuden - 15 Jun 2002