Data Access Library for Eiffel contents structure

Chapter III. DALE classes hierarchy

Preface

This chapter describes the hierarchy of DALE's interface classes together with some of their dependencies. Interfaces of some classes are described partially to exclude features which are rarely used and some pre- and postconditions are not very important.

DALE classes hierarchy:

Structure of DALE's classes

Brief classes survey:

Class Description
ODBC_ELEMENT * abstract class which presents the notion of an ODBC access element: environment, connection or statement
SESSION presents the notion of an ODBC environment
DATABASE presents the notion of an ODBC connection to a data source
SIMPLE_QUERY * presents the notion of an ODBC statement
QUERY kind of SIMPLE_QUERY which "knows" how to construct, prepare and execute a SQL statement as a kind of ODBC statement
SQL_SELECT kind of QUERY which incapsulates SQL SELECT statement
SQL_INSERT kind of QUERY which incapsulates SQL INSERT statement
SQL_UPDATE kind of QUERY which incapsulates SQL UPDATE statement
SQL_DELETE kind of QUERY which incapsulates SQL DELETE statement
RECORDSET results from executed ODBC statement in a form of a collection of records
RS_CURSOR a cursor for RECORDSET; depending on the chosen scrolling mode, it can be monodirectional, or bidirectional and supports absolute and relational movements in recordset
RECORD unit of a recordset; comprised of the FIELDs
DB_CATALOG * an abstract DALE'S catalog which "knows" how to fill itself up from different sources (see its effective heirs below)
TABLES kind of DB_CATALOG, containing a list of tables are currently presented in the database
PROCEDURES kind of DB_CATALOG, containing a list of stored procedures are currently presented in the database
TYPES kind of DB_CATALOG, containing a list of tables are currently defined in the database
FIELDS kind of DB_CATALOG, containing a list of fields which comprise the database table
PARAMETERS kind of DB_CATALOG, containing a list of parameters are currently defined in query, in particular, a stored procedure
DB_TABLE an element of the TABLES catalog; besides, this is also a recordset presenting the contents of the corresponding table
DB_PROCEDURE an element of the PROCEDURES catalog; besides, this is also a query which allows to execute the corresponding stored procedure and obtain result value
DB_TYPE an element of the TYPES catalog
FIELD an element of the FIELDS catalog or item of RECORD
ODBC_STATUS allows to find out the current ODBC status after a single operation or a group of operations
ODBC_ERROR_
DESCRIPTION
description of ODBC error
QUERY_COMPOSER provides easy and elegant way to construct typical SQL queries

Copyright © Object Tools -- info@object-tools.com
Last updated: 2005/02/02 11:51:24