ODAC (V9.5.15) study notes (i) General

has been using ODAC to do development, no time to study carefully, the current use of 3-storey structure, odac+tdatasetprovider+tclientdataset do data processing, there is no big problem. Next to develop B/s program, intends to use Odac+unigui to complete, data processing can actually be in accordance with 2-storey structure, compared to 3-storey structure to be simpler, performance is expected to be better. So we need to study the function of ODAC carefully. Old age, make a note lest forget. Most of the following materials are from ODAC's Help file, E is not too good, can only understand the meaning, inevitably wrong, read and use need to further verify.

1.1. Introduction

ODAC (Oracle data Access Components) is a dedicated group of controls for direct access to Oracle databases under RAD. The biggest feature is the ability to directly access the Oracle database without having to install the Oracle client, and encapsulate many of the features in the Oracle database.

ODAC is currently the latest version of 9.5.15, this article is based on this version of the introduction. This version supports multiple versions of Delphi, C++builder, and Lazarus, and supports VCL or FMX controls. This version is open source for direct access mode. The software is developed to support multiple platforms such as Android, IOS, WINDOWS32/64 and more. However, we develop Oracle-related programs, generally c/s/s or b/S architecture server-side programs, so only consider the development under the WINDOWS32/64 platform.

ODAC uses a pristine network connection (TCP/IP) to communicate with Oracle Server (Direct mode), bypassing Oracle's client programs for superior performance. Of course for stability you can also use Oracle's client connections.

1.2. Features

According to official documents, ODAC's 9.5.15 version has the following characteristics:

1, direct access to the Oracle database directly, no need to install the Oracle client, no need for BDE or ODBC database client engine, installation and deployment more convenient.

2. Support all server versions of Oracle, including 12c, 11g, 10g, 9i, 8i, 8.0, 7.3, Oracle Express Edition 11g/10g.

3, Support data offline mode (disconnected mode), after data buffering to the client, you can disconnect from the server to reduce the cost of Oracle server resources, all operations in local memory, when the need to submit data to reconnect the Oracle server.

4. Supports local indexing and filtering of all data types, including calculated fields and lookup fields.

5, automatic data update, including ODAC automatically generated update SQL or custom SQL, can be automatically submitted to the database server, or buffer mode manually submitted to the database.

6, support SQL script execution, so many upgrade scripts can be run automatically through the software.

7. Support Package and operation. Only one control is required to control the execution of all procedures and functions in a package.

8. Support Failover mode (Transparent application failover, TAF) when the database connection is disconnected for various reasons (most commonly for network reasons), ODAC can automatically reconnect and ensure that the client data is not lost. There is a huge advantage to database connectivity compared to traditional 2-tier architecture software.

9, support the monitoring of SQL statements, that is, SQLMonitor.

10, supports the memory table, can establish the data table in the client memory operation.

11. Support for Oracle's Message Queuing capabilities.

12, other functions, such as distributed transaction processing, double-byte character processing and so on.

ODAC (V9.5.15) study notes (i) General