dbOvernet applications are developed with the Delphi Professional edition. There is no requirement for the more expensive Delphi Client Server edition.

Client side components

dbOClientDataset: One component to provide all the functionality required for client-side application development. Retrieve, modify, insert, delete records with no code!

dbOClientConnection: (Optional) A distribution and broadcasting component used to pass messages between various participating dbOClientDatasets, like those participating in one to many relationships. The dbOClientConnection contains various common properties, like Port number, Server IP address, SOCKS properties and others that, when set in the dbOClientConnection, are automatically broadcast to all connected dbOClientDatasets.

The dbOClientConnection also handles multi-table cached updates, assembles and sorts grouped segmented transaction sets, and passes back error message records to participating tables.

or: use these components for specialized and/or unique requirements. The dbOClientDataset encapsulates all these, but there can be rare occasions where you need access to specific parts of the dbOClientDataset:

dbOAppServerClient: Communicates with the server, provides the link to and from the client-side data buffers.

dbODatasetBuffer: Contains the packaged data as transmitted from the server. Provides breakout functions to update linked data tables (dbODataset). Scrolls data into the dbODataset as needed to meet the visible data requirements.

dbOCommon: (Optional) A component that exposes routines contained inside the dbOClientDataset plus contains other functions. It provides pre-processing routines to pass updates to the server side, and includes data value converters and other common routines that can be used by all applications.

Server side components

dbOAppServer: Communicates with the client, provides the link to and from the server-side request broker. Manages user connections, creating and destroying communication sockets as needed.

dbORequestBroker: receives requests and dispatches them to the appropriate server object. Receives results and forwards them to the dbAppServer.

Server Objects: These classes derive from the ServerObject class and execute brokered requests, respond with data packets conveyed through the dbORequest broker to the dbOAppServer and back to the client

At the server side, the controls work with standard TDatabase, TQuery and TTable controls or the equivalent controls in various BDE alternates. The TQuery and TTable controls act as temporary data containers created by requests against the database. Data is packaged as an array of bytes and transmitted over the TCP/IP connection to the client.

dbOCommon: This component is rarely used, since the dbOClientDataset internalizes most of its functions. dbOCommon contains routines to convert, control and convey data in various ways. These automate processes to simplify the task of data communication between client side processing and server side updating, and vice-versa:

• Insert, Update and Delete handlers
• ExecuteSQLUpdate;
• ExecuteCachedUpdate;
• CacheSQLUpdate;

Asynchronous (blocking) control

• SendAndWait;

Unique number generator

• Delay;
• GetGUID;

Number converters

• GetFloatVal(Text: string): Extended;
• GetLongVal(Text: string): LongInt;
• GetIntVal(Text: string): Integer;
• Strip(Text: string): string;
• GetFloatValue;
• SetFloatValue;
• GetIntegerValue;
• SetIntegerValue;
• GetDateValue;

Global variables

• LastGUID: string;
• GlobalUserID: Extended;
• GlobalQueueTime,GlobalWaitTime: LongInt;
• CacheList: TStringList;

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