Introduction

The ELS-QB is a visual interface used for the creation of complex queries, it may be utilized in much the same manner as MS-Access query design interface.

The ELS-QB visual interface essentially consists of the following five panes:

        Connections pane, in which the user defines or manipulates database connections,

        DB Browser pane, which displays the database objects for the currently active database connection in the Connections pane,

        Relations pane, in which relations and joins are defined for selected database objects,

        Columns pane, in which the user selects fields and defines criteria, as well as grouping and sorting,

        SQL pane, in which the finalized SQL command is displayed or directly entered.

With the Connections pane the user can create database connections for various types of database engines including MS-SQL Server, MS-Access, Oracle, DB2, as well as, for other ODBC complaint OLE DB providers. Using the DB Browser pane one may display the database objects, such as tables, views and stored-procedures, for any connection defined in the Connections pane. The user may drag-drop objects from the DB Browser pane into the Relations pane, in which relations or joins between objects may be defined. In the Columns pane the user may define fields or expressions using the Columns functions toolbar. In addition, criteria, grouping and sorting may be defined via this Columns pane. All these operations together construct the SQL statement displayed in the SQL pane. Moreover, the SQL pane is an advance editor comparable with the Visual C++ editor with color syntax, edit operations, find/replace and advance selection features. In this editor the user may manually enter the SQL statement, which upon update will synchronize the other panes. At the end the user may verify and run the query, and the result will be displayed in the Result tab-view of the query builder. Both the SQL pane and the grid in the Result tab-view have export and print support, so that the user may export the content to MS-Office applications (or simply print this content).

The ELS-QB component has integrated ADO data access mechanisms, so that the user may dynamically create any database connection, using the Connection Manager interface integrated in the Connections pane. Each query builder instance (or session window) may have its own associated storage location, a directory in which all the connection binary files for the instance are created. Each connection created in the Connections pane has a different such binary file, in which all the queries under that connection are stored. All file-processing mechanisms are built-in into the ELS-QB component.