GB2405964A

GB2405964A - Database access

Info

Publication number: GB2405964A
Application number: GB0321561A
Authority: GB
Inventors: Olivier Roger
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2003-09-15
Filing date: 2003-09-15
Publication date: 2005-03-16
Also published as: GB0321561D0

Abstract

A user inputs a reference via an interface to a server; the server accesses the database, the database returning information relating to that reference only, to the server, and the server sends information pertaining to the reference to the user via the interface.

Description

DATABASE ACCESS METHOD

The invention relates to a system wherein a server is used to access a database. The invention is particularly applicable to a Object Request Broker (ORB) environment. An ORB is a software architecture that allows some objects (client objects) to access remote object (server objects) as if they were located on the same machine. In general lo architecture has servers and clients. In order to be accessible, the remote objects must be made available on the network in a published manner i.e. bound. The process of publishing an object is giving it a unique name; this is called binding an object. This is done by a publisher, alternatively known as a "broker".

In a basic structure of systems to which the invention is applied, the server object has a broker, which makes the decision of creating a server object. In prior art systems a bound object is always created from the decision of its own server object. Figure l shows how the current art operates.

Figure l shows the flow of information in a typical system. The system comprises a client and a server with data flow between them. The client has the reference item i.e. the remote object which is already known (e.g. Is VOLKSWAGEN) this is then sent to the server to look up. This is done by the server, which generally creates and binds the object (VOLKSWAGEN) with a further string. In this case the server provides a reference which is sent back to the client. The client can then request an :.. ace:e.* 45: . object property e.g. colour to the server where after the server will return the property value, e.g. blue. A further option is that the client can change the colour by sending an execute method i.e. a function applied to the object e.g. change the colour of the car (respray car in red). Once this change has been implemented the value (i.e. red) is returned.

The system relies on an ORB call flow in which the decision in binding an object is server based. In other words it is always the server that decides to create an object and makes it available on the object.

The problem with this however is that it is highly desirable that the client rather than the server makes the decision to create an object on the server side.

Is In the invention e.g. the client notifies the server of the creation and binding of an object, and this notification mechanism uses a dedicated remote object (bound on the server which hosts the created objects). It is a bit like an object factory.

The creation of the object may use for example uses the following steps: a) the client informs the server of the creation of an object b) a dedicated remote object bound on the server creates the object and binds it with a specific unique ID, e.g. the cocatenation of the class 2s name and a computed hash code c) the dedicated remote object sends back the unique ID to the client, so that the client knows the name of the bound object.

:. . .e ë.. If': d) with the name the client can create a local reference to the new remote object e) the client then dialogues with the remote object as usual.

s Example 1

Figure 2 shows an example of the information system where customers are registered in a server and the client hosts a Graphic User Interface.

This is the visible part of the client software, from the user point of view.

lo The client retrieves the list of customers names from the server. Through the GUI of the client the user selects a name in order to retrieve all the information from the server. The client asks the server to create a remote customer object, and the relevant information is shown on the interface.

is The decision of the creation of a server object is now made on the client.

It is possible thanks to the use of a dedicated bound server object.

The advantages are the client does not have to know in advance the name of the object instances on the server. Also the server does not have to ho bind a lot of objects so that the client can find the desired one. Only the asked objects are created and bound. This reduces memory consumption on the server and optimises the network traffic between the client and the server

Is Example 2

Figure 3 illustrates a further example of the invention. Figure 3a and 3b shows an example of the prior art and the invention respectively. : . . 4 '.

Both figures show the data flow from and to the user (left-hand side) to a database (right-hand side) via a graphic user interface and a server.

In the example the user requests a patient details using a reference. The s server is to return to the user via the interface name of the patient. In the prior art the server must create a reference for all the patients. As a consequence the memory used is large and includes a list of all patients.

In contrast, in the invention only a single reference to the patient is lo created. From this reference the name (or another attribute of the reference) can be selected and returned.

In other words, the server bids searching objects dedicated to finding a given information e.g. patient in a database and a match (or matching list of names) is returned. In this list, the user selects an entry (on the client side). The client asks the server for the creation of the corresponding object and then can retrieve all the properties of the newly bound server object to display on its interface.

Example 3

An operator on the client application has the list of telephone numbers of the subscribers he wants to know the detailed bill of this customer. The client application asks the server for the creation of the remote object corresponding to the subscriber and can then retrieve the information it Is wants from this remote object. The advantage here is that the server does not have to transmit all the information about the subscriber and does not have to bind the remote objects corresponding to the whole list of subscribers

Claims

::: :: -' :. : :: is . --e CLAIMS

1. A method of accessing a database comprising the following steps: a) a user inputting a reference, via an interface to a server; b) the server accessing the database, the database returning information relating to that reference only, to the server, and c) the server sending information pertaining to the reference to the user via the interface. lo

2. A method as claimed in claim l wherein after step c) the user and server communicate further via the interface such that only specific user requested information from within said database returned information is sent from the server to the user.